Effect of sintering temperature on the dielectric and impedance properties of rare-earth manganese ErMnO3

Effect of sintering temperature on the dielectric and impedance properties of rare-earth manganese ErMnO3 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of sintering temperature on the dielectric and impedance properties of rare-earth manganese ErMnO 3 Wei Li, Xiaoyu Wu, Ziheng Huang, Weitian Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7295332/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Oct, 2025 Read the published version in Journal of Electroceramics → Version 1 posted 14 You are reading this latest preprint version Abstract Polycrystalline ErMnO 3 ceramics were synthesized through a solid-state reaction method and systematically characterized to investigate the influence of sintering temperature (ranging from 1300 to 1450 ℃) on their structural, microstructural, and electrical properties. X-ray diffraction analysis confirmed the formation of a single hexagonal perovskite phase (space group P6 3 cm) at temperatures above 1350 ℃. Scanning electron microscopy observations indicated improved densification and progressive grain growth with increasing sintering temperature; however, abnormal grain overgrowth was observed at 1450 ℃. X-ray photoelectron spectroscopy revealed that Er 3+ is the predominant oxidation state, while higher sintering temperatures facilitated the generation of oxygen vacancies, leading to the partial reduction of Mn 3+ to Mn 2+ . Dielectric measurements showed that the sample sintered at 1400 ℃ exhibited the highest permittivity ( ε ′ = 1.532×10 5 at 1 kHz and 300 K) and the lowest dielectric loss (tanδ = 2.270 at 1 kHz and 300 K), indicating optimal polarization behavior. Impedance spectroscopy further demonstrated that this sample had the lowest equivalent resistance, suggesting enhanced charge carrier mobility. Reduced electric modulus values in the mid- to high-frequency range supported the conclusion that structural defects were effectively suppressed. These findings highlight the critical role of sintering temperature in determining the electrical performance of ErMnO 3 ceramics, with 1400 ℃ yielding the most favorable combination of structural stability, defect minimization, and improved dielectric response, thereby enhancing its potential for application in multifunctional electronic devices. Rare earth Manganese Perovskite Dielectric properties Impedance Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1 Introduction Rare-earth manganites (RMnO 3 , where R denotes a rare-earth element) have attracted considerable attention due to their prominent multiferroic properties, characterized by the coexistence of multiple ferroic orders-such as ferroelectricity, ferromagnetism, or antiferromagnetism-and the coupling interactions between them. These findings establish a robust basis for developing next-generation multifunctional electronic devices [ 1 – 3 ]. The crystal structure of RMnO 3 compounds is predominantly determined by the ionic radius of the A-site rare-earth element, which generally results in the formation of either orthorhombic (o-RMnO₃) or hexagonal (h-RMnO₃) perovskite structures [ 4 , 5 ]. To date, orthorhombic variants such as TbMnO₃ and DyMnO₃ have been thoroughly investigated for their pronounced magnetoelectric coupling and well-established multiferroic characteristics [ 6 – 8 ]. In contrast, studies on hexagonal RMnO₃ compounds, such as YMnO₃, HoMnO₃, and ErMnO₃, remain relatively limited [ 9 ], particularly regarding their dielectric properties, charge transport mechanisms, and the fundamental processes governing these phenomena. ErMnO₃, a hexagonal rare-earth manganite, exhibits a crystal structure defined by the P6₃cm space group [ 10 ]. Its inherent spontaneous polarization, along with its distinctive layered crystal structure, renders it highly suitable for potential applications in areas such as spin-polarization modulation, electron strictive response, and multifunctional coupling phenomena. The electrical characteristics of ErMnO₃ are shaped by its inherent crystal structure and chemical makeup, yet are significantly impacted by fabrication conditions, notably the sintering temperature [ 11 ]. This parameter plays a crucial role in determining microstructural characteristics such as grain size, porosity, densification, and defect density, all of which influence polarization behavior, charge transport, and interfacial properties. Consequently, meticulous regulation of sintering temperature is crucial for enhancing the structural integrity and electrical efficiency of ErMnO₃ ceramics in practical applications [ 12 ]. Previous studies have demonstrated that sintering temperature exerts a significant influence on the structural and functional properties of rare-earth manganites [ 13 , 14 ]. However, there remains a notable lack of systematic studies that correlate sintering parameters with microstructural evolution, dielectric response, and impedance behavior in ErMnO 3 ceramics. A thorough understanding of how processing conditions dictate microstructural development and the resulting electrical properties is essential for optimizing material performance. Elucidating the fundamental interrelationships among fabrication parameters, defect chemistry, and charge transport mechanisms in this system will yield critical insights into performance variability and enhance their functional applicability in electroceramic devices [ 15 ]. Motivated by these critical research imperatives, ErMnO 3 ceramics were synthesized using a conventional solid-state reaction method [ 16 , 17 ] and subsequently sintered at temperatures ranging from 1300 ℃ to 1450 ℃ (specifically at 1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃). This study systematically examines the influence of sintering temperature on key material characteristics: phase composition, grain morphology evolution, and functional electrical properties. Comprehensive structural, microstructural, and chemical state analyses, together with measurements of dielectric constant, dielectric loss, complex impedance spectra, and the real component of the electric modulus (M′), were conducted. The primary objectives of this investigation are to establish clear correlations between sintering temperature, the resulting structural and microstructural features, and the dielectric-impedance response in ErMnO 3 ceramics; to identify the optimal sintering conditions for maximizing functional performance; and to provide fundamental mechanistic insights, supported by robust experimental evidence, that are essential for advancing the rational design and practical application of these multiferroic materials in next-generation electronic devices. 2 Experimental procedures Polycrystalline ErMnO₃ ceramics were fabricated using the traditional solid-state reaction technique. High-purity erbium oxide (Er₂O₃, 99.99%) and manganese dioxide (MnO₂, 99.9%) were used as starting materials, weighed precisely according to the stoichiometric ratio of Er₂O₃:MnO₂ = 1:2. All raw materials were sourced from Macklin Chemical Co., Ltd., Shanghai, China. The fundamental reaction involved in the synthesis is as follows: The precursor powders were thoroughly blended and pre-calcined at 1000 ℃ in air for 4 h to initiate the solid-state reaction. Subsequently, the calcined powders were ground and compacted into pellets with a diameter of ~ 12 mm and thickness of ~ 2 mm. To systematically investigate the effect of sintering temperature on the structural and electrical behavior of ErMnO₃ ceramics, the green bodies were sintered in air at 1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃ for 4 h. The crystal structure was analyzed using X-ray diffraction (XRD) with Cu Kα radiation (λ = 1.5418 Å) in BraggBrentano geometry across a 2θ angle range of 10° − 80° in air at room temperature, employing an X’Pert3 Powder diffractometer (PANalytical, The Netherlands). Rietveld refinement was performed on the XRD pattern of the 1400 ℃ sample to extract accurate structural details. Surface morphology was characterized by field-emission scanning electron microscopy (FE-SEM: JEOL JSM-7800F). X-ray photoelectron spectroscopy (XPS; Thermo Scientific K-Alpha, Al-Kα radiation) was employed to analyze the chemical states of Er 4d, Mn 2p, and O 1s, with adventitious carbon (C 1s = 284.8 eV) used as the charge reference. The electrical performance was performed using the HIOKI 3532-50 LCR HiTester, covering the frequency range from 100 Hz to 1 MHz and temperatures from 220 K to 380 K. Prior to electrical characterization, conductive silver paste was applied to both surfaces of the ceramic discs and annealed at 600 ℃ for 20 min to ensure stable and reproducible electrode contact. 3 Results and discussion 3.1 XRD characterization The phase evolution and crystal structure of ErMnO₃ ceramics sintered at different temperatures (1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃) are shown in Fig. 1. The sample sintered at 1300 ℃ exhibits weak secondary diffraction peaks associated with Mn 3 O 4 and Er 2 O 3 , as shown in Fig. 1(a), indicating that the solid-state reaction remained incomplete at this temperature. In contrast, samples sintered at 1350 ℃ and above display pure-phase ErMnO 3 with all diffraction peaks indexed to a hexagonal structure (space group P6₃cm , PDF No. 14-0689), suggesting that higher sintering temperatures facilitate complete reaction and phase stabilization. Rietveld refinement was carried out on the XRD pattern of the sample sintered at 1400℃ to obtain detailed structural information. As illustrated in Fig. 1(b), the refinement resulted in low residual factors (R p = 7.0%, R wp = 9.3%), which indicate a high quality of fit. The derived structural parameters, including lattice constants, unit cell volume, and space group symmetry, are presented in Table 1, confirming the formation of a hexagonal ErMnO 3 phase. The corresponding atomic structure is displayed in the inset of Fig. 1(b). To further examine the microstructural characteristics, Williamson–Hall (W–H) analysis was conducted based on the following equation [18]: Here, β represents the full width at half maximum (FWHM), corrected for instrumental broadening (in radians), θ is the Bragg angle, k is the shape factor (typically 0.9), λ is the X-ray wavelength, D is the crystallite size, and ε denotes the lattice microstrain. A linear fit of βcosθ versus 4sinθ, as shown in Fig. 1(c), provided a grain size of ~ 1μm for the 1400 ℃ sample, along with a relatively low microstrain value. The results indicate that the sample possesses a highly dense and well-ordered crystalline structure with very few lattice imperfections, likely contributing to its improved electrical characteristics. 3.2 SEM images SEM images of the fractured surfaces of ErMnO₃ ceramics sintered at different temperatures are presented in Figs. 2(a-d). The micrographs reveal well-defined, densely packed grains indicative of successful sintering for all compositions. A clear evolution in the microstructure morphology is observed with increasing sintering temperature. The grain size of ErMnO₃ ceramics exhibits a significant increase, while the microstructural densification demonstrates notable improvement. However, the grain growth behavior exhibits a distinct temperature dependence and is governed by thermodynamic driving forces. At 1300 ℃ (Figs. 2a and 2e), insufficient thermal energy leads to a reduced diffusion rate and limited grain boundary mobility [19]. As a result, grain growth is significantly impeded [20], interparticle bonding is poor, and numerous pores remain on the surface. In addition, some particles remain partially un-sintered, indicating characteristics typical of the initial stage of sintering. At this stage, surface energy primarily drives the process, and grain growth proceeds slowly. The grain sizes vary widely, ranging from about 0.6 to 1.3 μm, indicating significant microstructural heterogeneity. Such unevenness hinders the formation of continuous charge conduction pathways and may cause localized distortions in the electric field. As the temperature increases to 1350 ℃ (Figs. 2b and 2f), the sintering driving force is enhanced, atomic mobility increases, and both grain boundary and bulk diffusion mechanisms become active. This promotes significant material exchange and neck growth between grains, effectively accelerating densification. Grains become noticeably larger and more regular in shape, with significantly reduced porosity and tighter intergranular bonding. The grain size distribution narrows to a range of 0.8 to 1.5 μm, reflecting enhanced uniformity in grain dimensions. This improved uniformity minimizes space charge buildup and localized impedance fluctuations, resulting in better dielectric behavior and electrical stability. At 1400 ℃ (Figs. 2c and 2g), the ceramic achieves an optimal sintering state, reflecting a balanced interplay between thermodynamic and kinetic factors. The grains develop into well-defined polyhedral structures with clear boundaries and densely packed interfaces. Porosity is almost entirely eliminated, indicating that the sintering process is nearly complete. A dynamic equilibrium is established between grain growth and pore removal, which effectively inhibits abnormal grain coarsening. Adjacent grains exhibit favorable alignment, characterized by a symmetrical grain size distribution primarily within the range of 1.0 to 1.4 μm, thus ensuring excellent microstructural uniformity. This refined microstructure minimizes leakage pathways and enhances coherent polarization, contributing to stabilized dielectric properties and optimized impedance behavior. Therefore, 1400 ℃ is determined to be the optimal temperature for achieving superior microstructural refinement and enhanced electrical performance. At 1450 ℃ (Figs. 2d and 2h), excessive grain growth leads to the formation of abnormally large grains, a phenomenon known as abnormal grain growth (AGG) [21]. This occurs due to uneven migration rates of grain boundaries, where larger grains consume smaller ones, resulting in the development of oversized "super grains."[22] [22] Such growth induces structural inhomogeneity and causes grain boundaries to become less distinct. Furthermore, at elevated temperatures, the decrease in grain boundary energy and interfacial tension diminishes the structure’s capacity to relieve internal stresses, rendering grain boundaries unstable and susceptible to collapse or stress-induced separation. Over-sintering can lead to the emergence of additional defects or the precipitation of secondary phases, which may undermine the structural stability of the material. Consequently, the grain size distribution notably shifts toward larger grains (2.0-3.5 μm), which adversely affects electric field uniformity and may cause deteriorated electrical performance, including increased dielectric losses and the formation of enhanced conductive pathways. Sintering temperature plays a critical role in regulating the thermally driven diffusion processes that dominate the grain growth and densification behavior of ErMnO₃ ceramics [23]. The specimen sintered at 1400 ℃ exhibits an optimal combination of grain shape, uniform grain size, and high densification. In contrast, sintering at 1450 ℃ results in excessive grain growth, microstructural irregularities, and a decline in electrical performance. Accurate regulation of the sintering temperature is essential to achieve highly dense ErMnO₃ ceramics with uniform microstructures and enhanced electrical performance. 3.3 XPS analysis Given the significant impact of ionic valence states on dielectric properties, XPS analysis was conducted on ErMnO₃ ceramics sintered at various temperatures. Typical results for the sample sintered at 1400 ℃ are shown in Fig. 3. The survey spectrum (Fig. 3a) distinctly exhibits the signature peaks of Er, Mn, and O, verifying the effective integration of these elements within the ceramic matrix. The C 1s signal is generally ascribed to surface carbon contamination introduced during measurement and is often employed as a reference for binding energy calibration [24]. As illustrated in Fig. 3b, a prominent Er 4d peak is observed at a binding energy of approximately 168.2 eV, which corresponds to the characteristic Er 3+ state [25]. The absence of other oxidation states suggests that erbium predominantly adopts the +3 oxidation state within the ErMnO 3 lattice, thereby contributing to enhanced structural stability. Figure 3(c) displays the high-resolution Mn 2p spectrum, which reveals the coexistence of Mn 3+ and Mn 2+ oxidation states. The Mn 3+ 2p 3/2 peak is observed at approximately 642.5 eV, while the Mn 2+ 2p 3/2 peak is detected at around 641 eV [26]. This indicates that a partial reduction of Mn 3+ to Mn 2+ occurred during the sintering process. At elevated temperatures, lattice oxygen tends to be released, promoting the formation of oxygen vacancies and altering the material's defect chemistry [27]. To maintain local charge neutrality, a portion of Mn 3+ ions undergoes reduction to Mn 2+ . The corresponding defect reactions can be expressed as follows: Additionally, the high-resolution O 1s spectrum in Fig. 3(d) was deconvoluted into three distinct peaks at approximately 529.2 eV, 531.3 eV, and 533.1 eV, which correspond to lattice oxygen (LO), oxygen vacancy-related species (VO), and adsorbed oxygen (CO), respectively [28]. Elevated temperatures enhance lattice vibrations, supplying sufficient energy for certain oxygen atoms to overcome bonding constraints and leave the lattice, thereby generating oxygen vacancies. This phenomenon further verifies that sintering at elevated temperatures encourages lattice oxygen loss and the generation of such vacancies. These results are similar with prior studies on vacancy-driven multivalency in perovskite oxides [29,30]. As is known, oxygen vacancies are closely linked to the coexistence of multiple manganese valence states and indicate the presence of intrinsic structural defects in the material. As a key type of point defect, oxygen vacancies exert a profound influence on the electrical properties of ErMnO 3 ceramics. On one hand, oxygen vacancies enhance carrier mobility within the lattice, thereby reducing impedance and increasing electrical conductivity. On the other hand, under an alternating electric field, these vacancies tend to accumulate and form space charge polarization regions, which enhance the dielectric response-particularly the dielectric constant in the low-frequency range. Furthermore, a moderate concentration of oxygen vacancies can promote polarization and improve overall dielectric performance. However, excessive vacancy concentrations may lead to increased dielectric loss and compromise electrical stability. 3.4 Dielectric measurements To investigate the influence of sintering temperature on the electrical properties of ErMnO 3 ceramics, the dielectric characteristics were systematically evaluated for samples sintered at different temperatures. A comprehensive analysis of dielectric behavior was carried out across a frequency range of 10 2 to 10 6 Hz and a temperature interval from 220 K to 380 K, with the objective of elucidating the effect of sintering conditions on the material's dielectric response. Figure 4 shows the variation of dielectric constant ( ε ′) with frequency for ErMnO₃ ceramic sample sintered at different temperatures. As shown, all samples display a gradual reduction in dielectric constant with increasing frequency, reflecting characteristic frequency-dependent dispersion. This phenomenon is primarily attributed to the different polarization mechanisms-such as space charge polarization, interfacial polarization, and dipolar polarization-responding differently to the external electric field. At low frequencies, polarization processes can readily follow the field, resulting in higher ε′ values. In contrast, at higher frequencies, the inability of these mechanisms to keep pace leads to a significant reduction in ε′ [31]. Notably, the sintering temperature has a significant influence on the magnitude of the dielectric constant. As the sintering temperature increases from 1300 ℃ to 1400 ℃, ε′ rises continuously, reaching a maximum at 1400 ℃ ( ε ′ = 1.532×10 5 at 1 kHz and 300 K). These findings suggest that the sample sintered at this temperature displays the most developed crystal structure, highest density, minimal grain boundary imperfections, and greatest capacity for space charge accumulation. This effect mainly arises from the enhanced thermal activation of charge carriers and improved dipole alignment at elevated temperatures, both facilitating increased polarization [32]. Figure 5 illustrates that all samples exhibit a decrease in tan δ with increasing frequency, which is indicative of typical frequency dispersion behavior. At low frequencies, significant accumulation of space charge at grain boundaries enhances interfacial polarization, resulting in elevated dielectric loss. In contrast, at high frequencies, the delayed polarization response leads to a marked reduction in tan δ. With increasing temperature, all samples display an increase in low-frequency tan δ, primarily due to thermally activated charge carriers that promote charge transport and consequently increase dielectric loss. Additionally, Fig. 5(e) compares the tanδ–frequency response (measured at 300 K) of samples sintered at different temperatures. The sample sintered at 1400 ℃ is found to exhibit the lowest dielectric loss across the entire frequency range (tanδ = 2.270 at 1 kHz and 300 K), indicating well-developed grains, high structural densification, and minimal grain boundary defects, which collectively contribute to the effective suppression of energy dissipation during polarization. In contrast, samples sintered at 1300 ℃ and 1350 ℃ display significantly higher tanδ values, particularly at lower frequencies, suggesting increased grain boundary density, higher porosity, and more pronounced polarization delays [33]. Meanwhile, the sample sintered at 1450 ℃ exhibits a slightly lower dielectric loss compared to those sintered at lower temperatures, but still remains higher than that of the 1400 ℃sample. This behavior is likely attributed to over-sintering-induced grain growth and the formation of localized structural defects, which negatively affect dielectric stability. The microstructure of polycrystalline manganese perovskites consists of a three-dimensional conductive framework formed by interconnected manganese grains, interspersed with insulating intergranular layers. This structural configuration, comprising alternating conductive and resistive regions, provides a basis for understanding charge transport mechanisms in these materials. Importantly, the interplay between grain connectivity and boundary resistance plays a decisive role in determining the macroscopic conductivity of perovskite oxide systems. Impedance analysis enables the separation and identification of resistive, capacitive, and relaxation characteristics associated with grains, grain boundaries, and electrode interfaces. Figure 6 presents the impedance spectra of the prepared samples. Each sample displays a distinct single semicircle in the low-frequency region, indicating that the electrical response is primarily governed by grain boundary effects. This behavior is consistent with the typical impedance characteristics of ionic ceramic materials [34]. As the measurement temperature increases, the semicircle diameters of all samples significantly decrease, reflecting enhanced thermal activation of charge carriers, improved electrical conductivity, and reduced impedance. This observation confirms the presence of a thermally activated conduction mechanism in ErMnO 3 ceramics and underscores the temperature dependence of their impedance behavior. The sintering temperature also has a pronounced effect on the impedance spectra. The sample sintered at 1300 ℃ exhibits a larger semicircular arc, indicating higher overall impedance, primarily attributed to increased grain boundary resistance. This can be associated with the smaller grain size and greater density of interfaces and defects at this sintering temperature, which hinder charge carrier mobility and reduce the efficiency of charge transport. With increasing sintering temperature to 1350 ℃ and 1400 ℃, the semicircle diameter in the impedance plots decreases progressively, indicating a substantial reduction in resistance and improved electrical conductivity. This enhancement is primarily attributed to grain growth and densification, which reduce the number of grain boundaries and the level of porosity, thereby facilitating more efficient charge carrier transport. The sample sintered at 1400 ℃ displays the smallest and most uniform semicircular arc, reflecting minimal resistance and an optimally developed microstructure. Therefore, 1400 ℃ is determined to be the optimal sintering temperature for achieving superior electrical performance in this study. However, when the sintering temperature is further increased to 1450 ℃, the semicircle diameter slightly increases, suggesting a rise in impedance. This phenomenon may be attributed to abnormal grain growth, which leads to the formation of excessively large grains and an inhomogeneous grain boundary distribution. Localized stress concentrations and the potential formation of microcracks can disrupt charge transport pathways, resulting in increased resistance and degraded electrical performance. Figure 6(e) compares the impedance spectra of samples sintered at different temperatures, measured at 300 K, clearly demonstrating that the sample sintered at 1400 ℃ exhibits the lowest complex impedance. In contrast, the samples sintered at 1300 ℃ and 1450 ℃ show elevated impedance levels, which can be attributed to grain boundary defects and structural inhomogeneity that hinder charge transport and compromise electrical stability. These findings highlight the crucial role of precise sintering temperature control in optimizing both grain and grain boundary microstructures, thereby enhancing the overall electrical performance of ErMnO 3 ceramics. Figure 7 presents the frequency-dependent real part of the electric modulus (M′) for samples sintered at different temperatures, measured over the temperature range of 220-380 K. Overall, M′ increases with frequency and tends to saturate at high frequencies, exhibiting typical frequency dispersion characteristics. This phenomenon mainly arises from the varying responses of polarization mechanisms-such as interfacial and space charge polarization-to the applied alternating current field across different frequencies. At low frequencies, polarization processes are fully developed, resulting in increased apparent capacitance and M′ values approaching zero; at high frequencies, polarization mechanisms cannot respond promptly, causing M′ to increase and saturate. The real component of the electric modulus (M′) decreases as temperature rises, indicating increased thermally activated carrier excitation and electrode polarization that diminish the intrinsic relaxation effects on the modulus. This suggests that M′ embodies the combined effects of carrier localization and polarization processes within the material. Notably, sintering temperature significantly influences both the amplitude and frequency dependence of M′. The sample sintered at 1300 ℃ exhibits the highest M′ values and strongest frequency dependence across the entire frequency range, indicative of numerous grain boundaries, porous microstructure, severe space charge accumulation, and pronounced polarization lag. With increasing sintering temperature to 1350 ℃, grain growth and reduced grain boundary impedance lead to decreased M′ values. The 1400 ℃ sample shows the lowest and most stable M′ curves, indicating uniform grains, dense microstructure, and minimal grain boundary polarization, corresponding to the optimal electrical performance. At 1450 ℃, although overall densification remains adequate, a slight increase and enhanced frequency dependence of M′ are observed, suggesting that over-sintering may lead to abnormal grain growth or localized structural instability, negatively affecting polarization behavior. To further validate the influence of sintering temperature on the modulus characteristics, Fig. 7(e) compares the M′–frequency behavior of samples sintered at different temperatures, measured at a fixed temperature of 300 K. The sample sintered at 1400 ℃ exhibits the lowest and most stable M′ values across the entire frequency range, indicating reduced grain boundary polarization and enhanced structural stability. 4 Conclusion Polycrystalline ErMnO 3 ceramics were synthesized via solid-state reaction to systematically evaluate the impact of sintering temperature (1300–1450 ℃) on structural, microstructural, and electrical properties. Rietveld-refined XRD confirmed progressive elimination of secondary-phase impurities with increasing temperature, achieving phase-pure hexagonal perovskite structure at elevated temperatures, with optimal crystallinity observed at 1400℃. SEM analysis revealed enhanced densification and uniform grain growth up to 1400℃, beyond which localized overgrowth and microstructural degradation occurred at 1450℃. Dielectric spectroscopy identified the 1400℃-sintered sample as exhibiting the highest dielectric constant and minimal loss, signifying superior polarization efficiency. Impedance analysis demonstrated minimized grain/grain boundary resistances at 1400℃, correlating with enhanced charge transport. Frequency dispersion in the electric modulus (M′) indicated dominant electrode polarization at low frequencies, while reduced M′ values at elevated temperatures reflected thermally activated carrier mobility and diminished polarization lag. These results unequivocally establish sintering temperature as a critical determinant of functional performance, with 1400℃ providing the optimal synergy of phase purity, microstructural homogeneity, and exceptional dielectric response. This work provides essential processing guidelines for advancing ErMnO 3 -based high-performance electroceramic devices. Declarations Acknowledgments This research was funded by the National Natural Science Foundation of China, Grant number 12374031 and the Graduate Innovation Foundation of Yantai University (No. KGIFYTU2407). Authors' contributions Wei Li and Xiaoyu Wu wrote the main manuscript text and prepared figures. Ziheng Huang fabricated and characterized the materials. Weitian Wang designed and supervised the project. All authors reviewed the manuscript and contributed to the discussion of the results. 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Withers, T. J. Frankcombe, L. Norén, A. Snashall, M. Kitchin, P. Smith, B. Gong, H. Chen, J. Schiemer, F. Brink, J. Wong-leung, Nat. Mater. 12, 821–826 (2013). R. M. German, Crit. Rev. Solid State Mat. Sci. 35 , 263–305 (2010). S. Chung, S. L. Kang, V. P. Dravid, J. Am. Ceram. Soc. 85 , 2805–2810 (2004). V. Koval, G. Viola, M. Zhang, M. Faberova, R. Bures, H. Yan, J. Eur. Ceram. Soc. 44 , 2886–2902 (2024). Y. Moualhi, M. Smari, H. Nasri, H. Rahmouni, Mater. Today Commun. 38 , 108529 (2024). Table Table 1 Lattice parameters and crystallographic information of ErMnO₃ ceramics sintered at 1400 ℃ obtained by Rietveld refinement. Sintering Temperature (℃) Space Group Lattice Parameters (Å) Cell Volume (ų) R p (%) R wp (%) χ² 1400 P6₃cm a=b=6.1134 c=11.3885 368.608 7.02 9.31 1.683 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 22 Oct, 2025 Read the published version in Journal of Electroceramics → Version 1 posted Editorial decision: Revision requested 06 Sep, 2025 Reviews received at journal 29 Aug, 2025 Reviews received at journal 20 Aug, 2025 Reviews received at journal 19 Aug, 2025 Reviewers agreed at journal 11 Aug, 2025 Reviews received at journal 11 Aug, 2025 Reviewers agreed at journal 11 Aug, 2025 Reviewers agreed at journal 11 Aug, 2025 Reviewers agreed at journal 10 Aug, 2025 Reviewers agreed at journal 10 Aug, 2025 Reviewers invited by journal 10 Aug, 2025 Editor assigned by journal 06 Aug, 2025 Submission checks completed at journal 06 Aug, 2025 First submitted to journal 04 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7295332","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":501293610,"identity":"19355491-8fa6-4533-b22d-0d97d49f0a5e","order_by":0,"name":"Wei Li","email":"","orcid":"","institution":"Yantai University","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Li","suffix":""},{"id":501293611,"identity":"c75d46d5-ebe5-4362-b939-75d6a0da787c","order_by":1,"name":"Xiaoyu Wu","email":"","orcid":"","institution":"Yantai University","correspondingAuthor":false,"prefix":"","firstName":"Xiaoyu","middleName":"","lastName":"Wu","suffix":""},{"id":501293612,"identity":"0772e77d-2f3c-4d9b-8000-8a0fe08dd2f2","order_by":2,"name":"Ziheng Huang","email":"","orcid":"","institution":"Yantai University","correspondingAuthor":false,"prefix":"","firstName":"Ziheng","middleName":"","lastName":"Huang","suffix":""},{"id":501293613,"identity":"4f392d12-ada7-4775-9dea-8d0dd487b02e","order_by":3,"name":"Weitian Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwUlEQVRIiWNgGAWjYPACGwjFQ5RiNjCZBlFNipbDJGgxuN9j+Lng1/nE/RIJjA/etjHImxPUcozHWHpm3+3EHokEZsO5bQyGOxsIaDE7xrtBmrcHrIVNmreNIcHgAGEtm3/z9pwDaWH/TayWbdI8Pw6AbWEmSov9sfxv1rwNycY9Zx42S845J2G4gZAWyeZjybd5/tjJtrcnH/zwpsxGnqAtYMDYxuDYwMDYAGRKEKMeBP4w2BOrdBSMglEwCkYgAACDcj8Wdxt2IQAAAABJRU5ErkJggg==","orcid":"","institution":"Yantai University","correspondingAuthor":true,"prefix":"","firstName":"Weitian","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-08-05 02:08:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7295332/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7295332/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10832-025-00438-5","type":"published","date":"2025-10-22T16:16:13+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89282850,"identity":"7871080f-af00-45a6-957a-660e7db7af3c","added_by":"auto","created_at":"2025-08-18 10:50:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":129080,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD patterns of ErMnO₃ ceramics sintered at different temperatures, (b) Rietveld refinement results of ErMnO₃ ceramics sintered at 1400 ℃, and (c) Williamson–Hall plot of the same sample.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/ee38458305603ec7c3fb1986.png"},{"id":89282851,"identity":"b97d275b-3dfd-4c99-99ad-114b5c7f6a48","added_by":"auto","created_at":"2025-08-18 10:50:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":185422,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of ErMnO₃ ceramics sintered at different temperatures: (a) 1300 ℃, (b) 1350 ℃, (c) 1400 ℃, and (d) 1450 ℃, respectively, and (e-h) grain size distribution of the corresponding samples.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/0ee8fa20c3cdeea48a6e8cba.png"},{"id":89282852,"identity":"cfa5d811-dbcf-410f-a954-dd34a976f8c7","added_by":"auto","created_at":"2025-08-18 10:50:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":169970,"visible":true,"origin":"","legend":"\u003cp\u003eXPS spectra of ErMnO₃ ceramics: (a) Survey scan, (b) Er 4d, (c) Mn 2p, and (d) O 1s. The solid lines are the fitting results using the XPS peak processing method.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/3d46d7eaf013d1b0de9616ea.png"},{"id":89283854,"identity":"640289bb-d332-45df-ad54-8176614bd3d0","added_by":"auto","created_at":"2025-08-18 10:58:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":216061,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency-dependent dielectric constant (\u003cem\u003eε′\u003c/em\u003e) of ErMnO₃ ceramic samples sintered at different temperatures over the temperature range of 220-380 K: (a) 1300 ℃, (b) 1350 ℃, (c) 1400 ℃, (d) 1450 ℃, and (e) Comparison of \u003cem\u003eε′ \u003c/em\u003eat 300 K.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/a6fd48d10c2f821e3dddeb83.png"},{"id":89283858,"identity":"197dca29-4350-4744-9349-3d21281b2f65","added_by":"auto","created_at":"2025-08-18 10:58:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":181485,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency dependence of dielectric loss (tanδ) for ErMnO₃ ceramics sintered at different temperatures measured in the temperature range of 220 K to 380 K: (a) 1300 ℃, (b) 1350 ℃, (c) 1400 ℃, (d) 1450 ℃, and (e) Comparison of tanδ at 300 K.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/185337d597e6a6cb14e03781.png"},{"id":89282860,"identity":"4c6b6761-cc42-40a3-a233-7c57f2cc8e57","added_by":"auto","created_at":"2025-08-18 10:50:33","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":161687,"visible":true,"origin":"","legend":"\u003cp\u003eNyquist plots of ErMnO₃ ceramics sintered at different temperatures measured over the temperature range of 220 K to 380 K: (a) 1300℃, (b) 1350℃, (c) 1400℃, (d) 1450℃, and (e) Comparison of impedance spectra at 300 K.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/9e33c4cc2c2d95e9386eb551.png"},{"id":89282856,"identity":"4ca68650-4a28-40da-bc2d-869b7ea22de1","added_by":"auto","created_at":"2025-08-18 10:50:32","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":186102,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency dependence of the real part of the electric modulus (M′) for ErMnO₃ ceramics sintered at different temperatures over the temperature range of 220 K to 380 K: (a) 1300℃, (b) 1350℃, (c) 1400℃, (d) 1450℃, and (e) Comparison of M′ at 300 K for samples sintered at different temperatures.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/c8705aac13a88d76fa72cbb8.png"},{"id":94490277,"identity":"b64c30e8-c95c-4378-86da-23e80a4df427","added_by":"auto","created_at":"2025-10-27 17:08:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1604672,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7295332/v1/1309c79b-31fc-4fbc-8c49-bd8c30f0b1cd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEffect of sintering temperature on the dielectric and impedance properties of rare-earth manganese ErMnO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eRare-earth manganites (RMnO\u003csub\u003e3\u003c/sub\u003e, where R denotes a rare-earth element) have attracted considerable attention due to their prominent multiferroic properties, characterized by the coexistence of multiple ferroic orders-such as ferroelectricity, ferromagnetism, or antiferromagnetism-and the coupling interactions between them. These findings establish a robust basis for developing next-generation multifunctional electronic devices [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The crystal structure of RMnO\u003csub\u003e3\u003c/sub\u003e compounds is predominantly determined by the ionic radius of the A-site rare-earth element, which generally results in the formation of either orthorhombic (o-RMnO₃) or hexagonal (h-RMnO₃) perovskite structures [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. To date, orthorhombic variants such as TbMnO₃ and DyMnO₃ have been thoroughly investigated for their pronounced magnetoelectric coupling and well-established multiferroic characteristics [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In contrast, studies on hexagonal RMnO₃ compounds, such as YMnO₃, HoMnO₃, and ErMnO₃, remain relatively limited [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], particularly regarding their dielectric properties, charge transport mechanisms, and the fundamental processes governing these phenomena.\u003c/p\u003e\u003cp\u003eErMnO₃, a hexagonal rare-earth manganite, exhibits a crystal structure defined by the P6₃cm space group [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Its inherent spontaneous polarization, along with its distinctive layered crystal structure, renders it highly suitable for potential applications in areas such as spin-polarization modulation, electron strictive response, and multifunctional coupling phenomena. The electrical characteristics of ErMnO₃ are shaped by its inherent crystal structure and chemical makeup, yet are significantly impacted by fabrication conditions, notably the sintering temperature [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This parameter plays a crucial role in determining microstructural characteristics such as grain size, porosity, densification, and defect density, all of which influence polarization behavior, charge transport, and interfacial properties. Consequently, meticulous regulation of sintering temperature is crucial for enhancing the structural integrity and electrical efficiency of ErMnO₃ ceramics in practical applications [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003ePrevious studies have demonstrated that sintering temperature exerts a significant influence on the structural and functional properties of rare-earth manganites [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, there remains a notable lack of systematic studies that correlate sintering parameters with microstructural evolution, dielectric response, and impedance behavior in ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics. A thorough understanding of how processing conditions dictate microstructural development and the resulting electrical properties is essential for optimizing material performance. Elucidating the fundamental interrelationships among fabrication parameters, defect chemistry, and charge transport mechanisms in this system will yield critical insights into performance variability and enhance their functional applicability in electroceramic devices [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMotivated by these critical research imperatives, ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics were synthesized using a conventional solid-state reaction method [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] and subsequently sintered at temperatures ranging from 1300 ℃ to 1450 ℃ (specifically at 1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃). This study systematically examines the influence of sintering temperature on key material characteristics: phase composition, grain morphology evolution, and functional electrical properties. Comprehensive structural, microstructural, and chemical state analyses, together with measurements of dielectric constant, dielectric loss, complex impedance spectra, and the real component of the electric modulus (M\u0026prime;), were conducted. The primary objectives of this investigation are to establish clear correlations between sintering temperature, the resulting structural and microstructural features, and the dielectric-impedance response in ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics; to identify the optimal sintering conditions for maximizing functional performance; and to provide fundamental mechanistic insights, supported by robust experimental evidence, that are essential for advancing the rational design and practical application of these multiferroic materials in next-generation electronic devices.\u003c/p\u003e"},{"header":"2 Experimental procedures","content":"\u003cp\u003ePolycrystalline ErMnO₃ ceramics were fabricated using the traditional solid-state reaction technique. High-purity erbium oxide (Er₂O₃, 99.99%) and manganese dioxide (MnO₂, 99.9%) were used as starting materials, weighed precisely according to the stoichiometric ratio of Er₂O₃:MnO₂ = 1:2. All raw materials were sourced from Macklin Chemical Co., Ltd., Shanghai, China. The fundamental reaction involved in the synthesis is as follows:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/p\u003e\n\u003cp\u003eThe precursor powders were thoroughly blended and pre-calcined at 1000 ℃ in air for 4 h to initiate the solid-state reaction. Subsequently, the calcined powders were ground and compacted into pellets with a diameter of ~\u0026thinsp;12 mm and thickness of ~\u0026thinsp;2 mm. To systematically investigate the effect of sintering temperature on the structural and electrical behavior of ErMnO₃ ceramics, the green bodies were sintered in air at 1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃ for 4 h.\u003c/p\u003e\n\u003cp\u003eThe crystal structure was analyzed using X-ray diffraction (XRD) with Cu K\u0026alpha; radiation (\u0026lambda;\u0026thinsp;=\u0026thinsp;1.5418 \u0026Aring;) in BraggBrentano geometry across a 2\u0026theta; angle range of 10\u0026deg; \u0026minus;\u0026thinsp;80\u0026deg; in air at room temperature, employing an X\u0026rsquo;Pert3 Powder diffractometer (PANalytical, The Netherlands). Rietveld refinement was performed on the XRD pattern of the 1400 ℃ sample to extract accurate structural details. Surface morphology was characterized by field-emission scanning electron microscopy (FE-SEM: JEOL JSM-7800F). X-ray photoelectron spectroscopy (XPS; Thermo Scientific K-Alpha, Al-K\u0026alpha; radiation) was employed to analyze the chemical states of Er 4d, Mn 2p, and O 1s, with adventitious carbon (C 1s\u0026thinsp;=\u0026thinsp;284.8 eV) used as the charge reference. The electrical performance was performed using the HIOKI 3532-50 LCR HiTester, covering the frequency range from 100 Hz to 1 MHz and temperatures from 220 K to 380 K. Prior to electrical characterization, conductive silver paste was applied to both surfaces of the ceramic discs and annealed at 600 ℃ for 20 min to ensure stable and reproducible electrode contact.\u003c/p\u003e"},{"header":"3 Results and discussion","content":"\u003cp\u003e3.1 XRD characterization\u003c/p\u003e\n\u003cp\u003eThe phase evolution and crystal structure of ErMnO₃ ceramics sintered at different temperatures (1300 ℃, 1350 ℃, 1400 ℃, and 1450 ℃) are shown in Fig. 1. The sample sintered at 1300 ℃ exhibits weak secondary diffraction peaks associated with Mn\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e and Er\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, as shown in Fig. 1(a), indicating that the solid-state reaction remained incomplete at this temperature. In contrast, samples sintered at 1350 ℃ and above display pure-phase ErMnO\u003csub\u003e3\u003c/sub\u003e with all diffraction peaks indexed to a hexagonal structure (space group \u003cem\u003eP6₃cm\u003c/em\u003e, PDF No. 14-0689), suggesting that higher sintering temperatures facilitate complete reaction and phase stabilization.\u003c/p\u003e\n\u003cp\u003eRietveld refinement was carried out on the XRD pattern of the sample sintered at 1400℃ to obtain detailed structural information. As illustrated in Fig. 1(b), the refinement resulted in low residual factors (R\u003csub\u003ep\u003c/sub\u003e = 7.0%, R\u003csub\u003ewp\u003c/sub\u003e = 9.3%), which indicate a high quality of fit. The derived structural parameters, including lattice constants, unit cell volume, and space group symmetry, are presented in Table 1, confirming the formation of a hexagonal ErMnO\u003csub\u003e3\u003c/sub\u003e phase. The corresponding atomic structure is displayed in the inset of Fig. 1(b).\u003c/p\u003e\n\u003cp\u003eTo further examine the microstructural characteristics, Williamson\u0026ndash;Hall (W\u0026ndash;H) analysis was conducted based on the following equation [18]:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/p\u003e\n\u003cp\u003eHere, \u0026beta; represents the full width at half maximum (FWHM), corrected for instrumental broadening (in radians), \u0026theta; is the Bragg angle, k is the shape factor (typically 0.9), \u0026lambda; is the X-ray wavelength, D is the crystallite size, and \u003cem\u003e\u0026epsilon;\u003c/em\u003e denotes the lattice microstrain.\u003c/p\u003e\n\u003cp\u003eA linear fit of \u0026beta;cos\u0026theta; versus 4sin\u0026theta;, as shown in Fig. 1(c), provided\u0026nbsp;a grain size of ~ 1\u0026mu;m for the 1400 ℃ sample, along with a relatively low microstrain value. The results\u0026nbsp;indicate that the sample possesses a highly dense and well-ordered crystalline structure with very few lattice imperfections, likely contributing to its improved electrical characteristics.\u003c/p\u003e\n\u003cp\u003e3.2 SEM images\u003c/p\u003e\n\u003cp\u003eSEM images of the fractured surfaces of\u0026nbsp;ErMnO₃ ceramics sintered at different temperatures are presented in Figs. 2(a-d). The micrographs reveal well-defined, densely packed grains indicative of successful sintering for all compositions. A clear evolution in the microstructure morphology is observed with increasing sintering temperature. The grain size of ErMnO₃ ceramics exhibits a significant increase, while the microstructural densification demonstrates notable improvement. However, the grain growth behavior exhibits a distinct temperature dependence and is governed by thermodynamic driving forces. At 1300 ℃ (Figs. 2a and 2e), insufficient thermal energy leads to a reduced diffusion rate and limited grain boundary mobility [19]. As a result, grain growth is significantly impeded [20], interparticle bonding is poor, and numerous pores remain on the surface. In addition, some particles remain partially un-sintered, indicating characteristics typical of the initial stage of sintering. At this stage, surface energy primarily drives the process, and grain growth proceeds slowly. The grain sizes vary widely, ranging from about 0.6 to 1.3 \u0026mu;m, indicating significant microstructural heterogeneity. Such unevenness hinders the formation of continuous charge conduction pathways and may cause localized distortions in the electric field.\u003c/p\u003e\n\u003cp\u003eAs the temperature increases to 1350 ℃ (Figs. 2b and 2f), the sintering driving force is enhanced, atomic mobility increases, and both grain boundary and bulk diffusion mechanisms become active. This promotes significant material exchange and neck growth between grains, effectively accelerating densification. Grains become noticeably larger and more regular in shape, with significantly reduced porosity and tighter intergranular bonding. The grain size distribution narrows to a range of 0.8 to 1.5 \u0026mu;m, reflecting enhanced uniformity in grain dimensions. This improved uniformity minimizes space charge buildup and localized impedance fluctuations, resulting in better dielectric behavior and electrical stability.\u003c/p\u003e\n\u003cp\u003eAt 1400 ℃ (Figs. 2c and 2g), the ceramic achieves an optimal sintering state, reflecting a balanced interplay between thermodynamic and kinetic factors. The grains develop into well-defined polyhedral structures with clear boundaries and densely packed interfaces. Porosity is almost entirely eliminated, indicating that the sintering process is nearly complete. A dynamic equilibrium is established between grain growth and pore removal, which effectively inhibits abnormal grain coarsening. Adjacent grains exhibit favorable alignment, characterized by a symmetrical grain size distribution primarily within the range of 1.0 to 1.4 \u0026mu;m, thus ensuring excellent microstructural uniformity. This refined microstructure minimizes leakage pathways and enhances coherent polarization, contributing to stabilized dielectric properties and optimized impedance behavior. Therefore, 1400 ℃ is determined to be the optimal temperature for achieving superior microstructural refinement and enhanced electrical performance.\u003c/p\u003e\n\u003cp\u003eAt 1450 ℃ (Figs. 2d and 2h), excessive grain growth leads to\u0026nbsp;the formation of abnormally large grains, a phenomenon known as abnormal grain growth (AGG) [21]. This occurs due to uneven migration rates of grain boundaries, where larger grains consume smaller ones, resulting in the development of oversized \u0026quot;super grains.\u0026quot;[22]\u003csup\u003e[22]\u003c/sup\u003e\u0026nbsp; Such growth induces structural inhomogeneity and causes grain boundaries to become less distinct. Furthermore, at elevated temperatures, the decrease in grain boundary energy and interfacial tension diminishes the structure\u0026rsquo;s capacity to relieve internal stresses, rendering grain boundaries unstable and susceptible to collapse or stress-induced separation. Over-sintering can lead to the emergence of additional defects or the precipitation of secondary phases, which may undermine the structural stability of the material. Consequently, the grain size distribution notably shifts toward larger grains (2.0-3.5 \u0026mu;m), which adversely affects electric field uniformity and may cause deteriorated electrical performance, including increased dielectric losses and the formation of enhanced conductive pathways.\u003c/p\u003e\n\u003cp\u003eSintering temperature plays a critical role in regulating the thermally driven diffusion processes that dominate the grain growth and densification behavior of ErMnO₃ ceramics [23]. The specimen sintered at 1400 ℃ exhibits an optimal combination of grain shape, uniform grain size, and high densification. In contrast, sintering at 1450 ℃ results in excessive grain growth, microstructural irregularities, and a decline in electrical performance. Accurate regulation of the sintering temperature is essential to achieve highly dense ErMnO₃ ceramics with uniform microstructures and enhanced electrical performance.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3.3 XPS analysis\u003c/p\u003e\n\u003cp\u003eGiven the significant impact of ionic valence states on dielectric properties, XPS analysis was conducted on ErMnO₃ ceramics sintered at various temperatures. Typical results for the sample sintered at 1400 ℃ are shown in Fig. 3. The survey spectrum (Fig. 3a) distinctly exhibits the signature peaks of Er, Mn, and O, verifying the effective integration of these elements within the ceramic matrix. The C 1s signal is generally ascribed to surface carbon contamination introduced during measurement and is often employed as a reference for binding energy calibration [24].\u003c/p\u003e\n\u003cp\u003eAs illustrated in Fig. 3b, a prominent Er 4d peak is observed at a binding energy of approximately 168.2 eV, which corresponds to the characteristic Er\u003csup\u003e3+\u003c/sup\u003e state [25]. The absence of other oxidation states suggests that erbium predominantly adopts the +3 oxidation state within the ErMnO\u003csub\u003e3\u003c/sub\u003e lattice, thereby contributing to enhanced structural stability.\u003c/p\u003e\n\u003cp\u003eFigure 3(c) displays the high-resolution Mn 2p spectrum, which reveals the coexistence of Mn\u003csup\u003e3+\u003c/sup\u003e and Mn\u003csup\u003e2+\u003c/sup\u003e oxidation states. The Mn\u003csup\u003e3+\u003c/sup\u003e 2p\u003csub\u003e3/2\u003c/sub\u003e peak is observed at approximately 642.5 eV, while the Mn\u003csup\u003e2+\u003c/sup\u003e 2p\u003csub\u003e3/2\u003c/sub\u003e peak is detected at around 641 eV [26]. This indicates that a partial reduction of Mn\u003csup\u003e3+\u003c/sup\u003e to Mn\u003csup\u003e2+\u003c/sup\u003e occurred during the sintering process. At elevated temperatures, lattice oxygen tends to be released, promoting the formation of oxygen vacancies and altering the material\u0026apos;s defect chemistry [27]. To maintain local charge neutrality, a portion of Mn\u003csup\u003e3+\u003c/sup\u003e ions undergoes reduction to Mn\u003csup\u003e2+\u003c/sup\u003e. The corresponding defect reactions can be expressed as follows:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/p\u003e\n\u003cp\u003eAdditionally, the high-resolution O 1s spectrum in Fig. 3(d) was deconvoluted into three distinct peaks at approximately 529.2 eV, 531.3 eV, and 533.1 eV, which correspond to lattice oxygen (LO), oxygen vacancy-related species (VO), and adsorbed oxygen (CO), respectively [28]. Elevated temperatures enhance lattice vibrations, supplying sufficient energy for certain oxygen atoms to overcome bonding constraints and leave the lattice, thereby generating oxygen vacancies. This phenomenon further verifies that sintering at elevated temperatures encourages lattice oxygen loss and the generation of such vacancies. These results are similar with prior studies on vacancy-driven multivalency in perovskite oxides [29,30].\u003c/p\u003e\n\u003cp\u003eAs is known, oxygen vacancies are closely linked to the coexistence of multiple manganese valence states and indicate the presence of intrinsic structural defects in the material. As a key type of point defect, oxygen vacancies exert a profound influence on the electrical properties of ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics. On one hand, oxygen vacancies enhance carrier mobility within the lattice, thereby reducing impedance and increasing electrical conductivity. On the other hand, under an alternating electric field, these vacancies tend to accumulate and form space charge polarization regions, which enhance the dielectric response-particularly the dielectric constant in the low-frequency range. Furthermore, a moderate concentration of oxygen vacancies can promote polarization and improve overall dielectric performance. However, excessive vacancy concentrations may lead to increased dielectric loss and compromise electrical stability.\u003c/p\u003e\n\u003cp\u003e3.4 Dielectric measurements\u003c/p\u003e\n\u003cp\u003eTo investigate the influence of sintering temperature on the electrical properties of ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics, the dielectric characteristics were systematically evaluated for samples sintered at different temperatures. A comprehensive analysis of dielectric behavior was carried out across a frequency range of 10\u003csup\u003e2\u003c/sup\u003e to 10\u003csup\u003e6\u003c/sup\u003e Hz and a temperature interval from 220 K to 380 K, with the objective of elucidating the effect of sintering conditions on the material\u0026apos;s dielectric response.\u003c/p\u003e\n\u003cp\u003eFigure 4 shows the variation of dielectric constant (\u003cem\u003e\u0026epsilon;\u003c/em\u003e\u0026prime;) with frequency for ErMnO₃ ceramic sample sintered at different temperatures. As shown, all samples display a gradual reduction in dielectric constant with increasing frequency, reflecting characteristic frequency-dependent dispersion. This phenomenon is primarily attributed to the different polarization mechanisms-such as space charge polarization, interfacial polarization, and dipolar polarization-responding differently to the external electric field. At low frequencies, polarization processes can readily follow the field, resulting in higher \u003cem\u003e\u0026epsilon;\u0026prime;\u0026nbsp;\u003c/em\u003evalues. In contrast, at higher frequencies, the inability of these mechanisms to keep pace leads to a significant reduction in\u0026nbsp;\u003cem\u003e\u0026epsilon;\u0026prime;\u0026nbsp;\u003c/em\u003e[31].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNotably, the sintering temperature has a significant influence on the magnitude of the dielectric constant. As the sintering temperature increases from 1300 ℃ to 1400 ℃, \u003cem\u003e\u0026epsilon;\u0026prime;\u003c/em\u003e rises continuously, reaching a maximum at 1400 ℃ (\u003cem\u003e\u0026epsilon;\u003c/em\u003e\u0026prime; = 1.532\u0026times;10\u003csup\u003e5\u003c/sup\u003e at 1 kHz and 300 K). These findings suggest that the sample sintered at this temperature displays the most developed crystal structure, highest density, minimal grain boundary imperfections, and greatest capacity for space charge accumulation. This effect mainly arises from the enhanced thermal activation of charge carriers and improved dipole alignment at elevated temperatures, both facilitating increased polarization [32]. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFigure 5 illustrates that all samples exhibit a decrease in tan \u0026delta; with increasing frequency, which is indicative of typical frequency dispersion behavior. At low frequencies, significant accumulation of space charge at grain boundaries enhances interfacial polarization, resulting in elevated dielectric loss. In contrast, at high frequencies, the delayed polarization response leads to a marked reduction in tan \u0026delta;. With increasing temperature, all samples display an increase in low-frequency tan \u0026delta;, primarily due to thermally activated charge carriers that promote charge transport and consequently increase dielectric loss.\u003c/p\u003e\n\u003cp\u003eAdditionally, Fig. 5(e) compares the tan\u0026delta;\u0026ndash;frequency response (measured at 300 K) of samples sintered at different temperatures. The sample sintered at 1400 ℃ is found to exhibit the lowest dielectric loss across the entire frequency range\u0026nbsp;(tan\u0026delta; = 2.270 at 1 kHz and 300 K), indicating well-developed grains, high structural densification, and minimal grain boundary defects, which collectively contribute to the effective suppression of energy dissipation during polarization. In contrast, samples sintered at 1300 ℃ and 1350 ℃ display significantly higher tan\u0026delta; values, particularly at lower frequencies, suggesting increased grain boundary density, higher porosity, and more pronounced polarization delays [33].\u0026nbsp;Meanwhile, the sample sintered at 1450 ℃ exhibits a slightly lower dielectric loss compared to those sintered at lower temperatures, but still remains higher than that of the 1400 ℃sample. This behavior is likely attributed to over-sintering-induced grain growth and the formation of localized structural defects, which negatively affect dielectric stability.\u003c/p\u003e\n\u003cp\u003eThe microstructure of polycrystalline manganese\u0026nbsp;perovskites consists of a three-dimensional conductive framework formed by interconnected\u0026nbsp;manganese\u0026nbsp;grains, interspersed with insulating intergranular layers. This structural configuration, comprising alternating conductive and resistive regions, provides a basis for understanding charge transport mechanisms in these materials. Importantly, the interplay between grain connectivity and boundary resistance plays a decisive role in determining the macroscopic conductivity of perovskite oxide systems. Impedance analysis enables the separation and identification of resistive, capacitive, and relaxation characteristics associated with grains, grain boundaries, and electrode interfaces.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFigure 6 presents the impedance spectra of the prepared samples. Each sample displays a distinct single semicircle in the low-frequency region, indicating that the electrical response is primarily governed by grain boundary effects. This behavior is consistent with the typical impedance characteristics of ionic ceramic materials\u0026nbsp;[34]. As the measurement temperature increases, the semicircle diameters of all samples significantly decrease, reflecting enhanced thermal activation of charge carriers, improved electrical conductivity, and reduced impedance. This observation confirms the presence of a thermally activated conduction mechanism in ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics and underscores the temperature dependence of their impedance behavior.\u003c/p\u003e\n\u003cp\u003eThe sintering temperature also has a pronounced effect on the impedance spectra. The sample sintered at 1300 ℃ exhibits a larger semicircular arc, indicating higher overall impedance, primarily attributed to increased grain boundary resistance. This can be associated with the smaller grain size and greater density of interfaces and defects at this sintering temperature, which hinder charge carrier mobility and reduce the efficiency of charge transport.\u003c/p\u003e\n\u003cp\u003eWith increasing sintering temperature to 1350 ℃ and 1400 ℃, the semicircle diameter in the impedance plots decreases progressively, indicating a substantial reduction in resistance and improved electrical conductivity. This enhancement is primarily attributed to grain growth and densification, which reduce the number of grain boundaries and the level of porosity, thereby facilitating more efficient charge carrier transport. The sample sintered at 1400 ℃ displays the smallest and most uniform semicircular arc, reflecting minimal resistance and an optimally developed microstructure. Therefore, 1400 ℃ is determined to be the optimal sintering temperature for achieving superior electrical performance in this study. However, when the sintering temperature is further increased to 1450 ℃, the semicircle diameter slightly increases, suggesting a rise in impedance. This phenomenon may be attributed to abnormal grain growth, which leads to the formation of excessively large grains and an inhomogeneous grain boundary distribution. Localized stress concentrations and the potential formation of microcracks can disrupt charge transport pathways, resulting in increased resistance and degraded electrical performance.\u003c/p\u003e\n\u003cp\u003eFigure 6(e) compares the impedance spectra of samples sintered at different temperatures, measured at 300 K, clearly demonstrating that the sample sintered at 1400 ℃ exhibits the lowest complex impedance. In contrast, the samples sintered at 1300 ℃ and 1450 ℃ show elevated impedance levels, which can be attributed to grain boundary defects and structural inhomogeneity that hinder charge transport and compromise electrical stability. These findings highlight the crucial role of precise sintering temperature control in optimizing both grain and grain boundary microstructures, thereby enhancing the overall electrical performance of ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics.\u003c/p\u003e\n\u003cp\u003eFigure 7 presents the frequency-dependent real part of the electric modulus (M\u0026prime;) for samples sintered at different temperatures, measured over the temperature range of 220-380 K. Overall, M\u0026prime; increases with frequency and tends to saturate at high frequencies, exhibiting typical frequency dispersion characteristics. This phenomenon mainly arises from the varying responses of polarization mechanisms-such as interfacial and space charge polarization-to the applied alternating current field across different frequencies. At low frequencies, polarization processes are fully developed, resulting in increased apparent capacitance and M\u0026prime; values approaching zero; at high frequencies, polarization mechanisms cannot respond promptly, causing M\u0026prime; to increase and saturate.\u003c/p\u003e\n\u003cp\u003eThe real component of the electric modulus (M\u0026prime;) decreases as temperature rises, indicating increased thermally activated carrier excitation and electrode polarization that diminish the intrinsic relaxation effects on the modulus. This suggests that M\u0026prime; embodies the combined effects of carrier localization and polarization processes within the material. Notably, sintering temperature significantly influences both the amplitude and frequency dependence of M\u0026prime;. The sample sintered at 1300 ℃ exhibits the highest M\u0026prime; values and strongest frequency dependence across the entire frequency range, indicative of numerous grain boundaries, porous microstructure, severe space charge accumulation, and pronounced polarization lag. With increasing sintering temperature to 1350 ℃, grain growth and reduced grain boundary impedance lead to decreased M\u0026prime; values. The 1400 ℃ sample shows the lowest and most stable M\u0026prime; curves, indicating uniform grains, dense microstructure, and minimal grain boundary polarization, corresponding to the optimal electrical performance. At 1450 ℃, although overall densification remains adequate, a slight increase and enhanced frequency dependence of M\u0026prime; are observed, suggesting that over-sintering may lead to abnormal grain growth or localized structural instability, negatively affecting polarization behavior.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo further validate the influence of sintering temperature on the modulus characteristics, Fig. 7(e) compares the M\u0026prime;\u0026ndash;frequency behavior of samples sintered at different temperatures, measured at a fixed temperature of 300 K. The sample sintered at 1400 ℃ exhibits the lowest and most stable M\u0026prime; values across the entire frequency range, indicating reduced grain boundary polarization and enhanced structural stability.\u003c/p\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003ePolycrystalline ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics were synthesized via solid-state reaction to systematically evaluate the impact of sintering temperature (1300\u0026ndash;1450 ℃) on structural, microstructural, and electrical properties. Rietveld-refined XRD confirmed progressive elimination of secondary-phase impurities with increasing temperature, achieving phase-pure hexagonal perovskite structure at elevated temperatures, with optimal crystallinity observed at 1400℃. SEM analysis revealed enhanced densification and uniform grain growth up to 1400℃, beyond which localized overgrowth and microstructural degradation occurred at 1450℃. Dielectric spectroscopy identified the 1400℃-sintered sample as exhibiting the highest dielectric constant and minimal loss, signifying superior polarization efficiency. Impedance analysis demonstrated minimized grain/grain boundary resistances at 1400℃, correlating with enhanced charge transport. Frequency dispersion in the electric modulus (M\u0026prime;) indicated dominant electrode polarization at low frequencies, while reduced M\u0026prime; values at elevated temperatures reflected thermally activated carrier mobility and diminished polarization lag. These results unequivocally establish sintering temperature as a critical determinant of functional performance, with 1400℃ providing the optimal synergy of phase purity, microstructural homogeneity, and exceptional dielectric response. This work provides essential processing guidelines for advancing ErMnO\u003csub\u003e3\u003c/sub\u003e-based high-performance electroceramic devices.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003eThis research was funded by the National Natural Science Foundation of China, Grant number 12374031 and the Graduate Innovation Foundation of Yantai University (No. KGIFYTU2407).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWei Li and Xiaoyu Wu wrote the main manuscript text and prepared figures. \u0026nbsp;Ziheng Huang fabricated and characterized the materials. Weitian Wang designed and supervised the project. All authors reviewed the manuscript and contributed to the discussion of the results.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of competing interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e All data generated or analysed during this study are included in this published article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eT. Goto, T. Kimura, G. Lawes, A. P. Ramirez, Y. Tokura, Phys. Rev. Lett. \u003cstrong\u003e92\u003c/strong\u003e, 257201 (2004).\u003c/li\u003e\n \u003cli\u003eR. Feyerherm, E. Dudzik, O. Prokhnenko, D. N. Argyriou, Phys. Rev. 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Today Commun. \u003cstrong\u003e38\u003c/strong\u003e, 108529 (2024).\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1\u0026nbsp;\u003c/strong\u003eLattice parameters and crystallographic information of ErMnO₃ ceramics sintered at 1400 ℃ obtained by Rietveld refinement.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003eSintering Temperature (℃)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 80px;\"\u003e\n \u003cp\u003eSpace Group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003eLattice Parameters (\u0026Aring;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 81px;\"\u003e\n \u003cp\u003eCell Volume (\u0026Aring;\u0026sup3;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003eR\u003csub\u003ep\u003c/sub\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003eR\u003csub\u003ewp\u003c/sub\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 79px;\"\u003e\n \u003cp\u003e\u0026chi;\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e1400\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 80px;\"\u003e\n \u003cp\u003e\u003cem\u003eP6₃cm\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 91px;\"\u003e\n \u003cp\u003ea=b=6.1134\u003c/p\u003e\n \u003cp\u003ec=11.3885\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 81px;\"\u003e\n \u003cp\u003e368.608\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e7.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e9.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 79px;\"\u003e\n \u003cp\u003e1.683\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-electroceramics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jecr","sideBox":"Learn more about [Journal of Electroceramics](https://link.springer.com/journal/10832)","snPcode":"10832","submissionUrl":"https://submission.nature.com/new-submission/10832/3","title":"Journal of Electroceramics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Rare earth, Manganese, Perovskite, Dielectric properties, Impedance","lastPublishedDoi":"10.21203/rs.3.rs-7295332/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7295332/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePolycrystalline ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics were synthesized through a solid-state reaction method and systematically characterized to investigate the influence of sintering temperature (ranging from 1300 to 1450 ℃) on their structural, microstructural, and electrical properties. X-ray diffraction analysis confirmed the formation of a single hexagonal perovskite phase (space group P6\u003csub\u003e3\u003c/sub\u003ecm) at temperatures above 1350 ℃. Scanning electron microscopy observations indicated improved densification and progressive grain growth with increasing sintering temperature; however, abnormal grain overgrowth was observed at 1450 ℃. X-ray photoelectron spectroscopy revealed that Er\u003csup\u003e3+\u003c/sup\u003e is the predominant oxidation state, while higher sintering temperatures facilitated the generation of oxygen vacancies, leading to the partial reduction of Mn\u003csup\u003e3+\u003c/sup\u003e to Mn\u003csup\u003e2+\u003c/sup\u003e. Dielectric measurements showed that the sample sintered at 1400 ℃ exhibited the highest permittivity (\u003cem\u003eε\u003c/em\u003e′ = 1.532×10\u003csup\u003e5\u003c/sup\u003e at 1 kHz and 300 K) and the lowest dielectric loss (tanδ = 2.270 at 1 kHz and 300 K), indicating optimal polarization behavior. Impedance spectroscopy further demonstrated that this sample had the lowest equivalent resistance, suggesting enhanced charge carrier mobility. Reduced electric modulus values in the mid- to high-frequency range supported the conclusion that structural defects were effectively suppressed. These findings highlight the critical role of sintering temperature in determining the electrical performance of ErMnO\u003csub\u003e3\u003c/sub\u003e ceramics, with 1400 ℃ yielding the most favorable combination of structural stability, defect minimization, and improved dielectric response, thereby enhancing its potential for application in multifunctional electronic devices.\u003c/p\u003e","manuscriptTitle":"Effect of sintering temperature on the dielectric and impedance properties of rare-earth manganese ErMnO3","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-18 10:50:28","doi":"10.21203/rs.3.rs-7295332/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-06T15:32:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-29T16:04:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-20T12:03:30+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-19T13:33:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"190581714887035192473711364225331007969","date":"2025-08-11T15:04:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-11T14:17:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"109753156030769206581965065001844362936","date":"2025-08-11T13:02:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"282350341238270247321543557431594747156","date":"2025-08-11T08:17:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"11775716984509029045473857410923028964","date":"2025-08-11T01:32:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"311871851317595311274394780012537376294","date":"2025-08-11T01:30:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-10T17:59:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-06T06:37:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-06T06:36:59+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Electroceramics","date":"2025-08-05T01:55:25+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-electroceramics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jecr","sideBox":"Learn more about [Journal of Electroceramics](https://link.springer.com/journal/10832)","snPcode":"10832","submissionUrl":"https://submission.nature.com/new-submission/10832/3","title":"Journal of Electroceramics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"32fef223-e451-4d51-ba48-a178f77baf48","owner":[],"postedDate":"August 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-27T16:31:32+00:00","versionOfRecord":{"articleIdentity":"rs-7295332","link":"https://doi.org/10.1007/s10832-025-00438-5","journal":{"identity":"journal-of-electroceramics","isVorOnly":false,"title":"Journal of Electroceramics"},"publishedOn":"2025-10-22 16:16:13","publishedOnDateReadable":"October 22nd, 2025"},"versionCreatedAt":"2025-08-18 10:50:28","video":"","vorDoi":"10.1007/s10832-025-00438-5","vorDoiUrl":"https://doi.org/10.1007/s10832-025-00438-5","workflowStages":[]},"version":"v1","identity":"rs-7295332","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7295332","identity":"rs-7295332","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}