Origin of giant dielectric permittivity and localized polarons supported electrical conduction in CaCu3Ti4O12 for extreme environment energy storage applications

Origin of giant dielectric permittivity and localized polarons supported electrical conduction in CaCu3Ti4O12 for extreme environment energy storage applications | 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 Article Origin of giant dielectric permittivity and localized polarons supported electrical conduction in CaCu 3 Ti 4 O 12 for extreme environment energy storage applications Subrata Karmakar, K. Ashok, N. Hussain Basha, P. K. Koochana, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8017034/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Feb, 2026 Read the published version in Scientific Reports → Version 1 posted 9 You are reading this latest preprint version Abstract We have synthesized CaCu 3 Ti 4 O 12 using a green synthesis route, employing an oxalate precursor obtained from a mixture of Averrhoa carambola (star fruit) fruit juice and aloe vera extract. The structural, microstructural, and ac electrical transport characteristics of this material were examined at high temperatures from 308 K to 773 K and in a wide frequency window of 100 Hz to 1 MHz. The Rietveld refinement of X-ray diffraction (XRD) and Raman spectroscopy demonstrates the single-phase body-centered cubic crystal structure with space group Im-3 and A g and F g vibrational modes due to rotations of TiO 6 octahedral and Ti-O-Ti anti-stretching vibrations of CaCu 3 Ti 4 O 12 . The fitted Nyquist plots ( \(\:{Z}^{{\prime\:}}\text{v}\text{s}.\:Z{\prime\:}{\prime\:})\) at different temperatures exhibit the grain and grain boundary contributions, and the semicircles shrink at higher temperatures, which disclosed the negative temperature coefficient of resistance (NTCR) behavior. Both grain ( R g ) and grain boundary resistance ( R gb ) and capacitances (C g , C gb ) diminished with temperature, and their activation energy was estimated to be ~ 0.56 eV and ~ 0.84 eV, respectively. The ac electrical conductivity increases with frequency and temperature due to thermally activated charge carriers, and the frequency exponent ( n ) remains nearly constant at low temperature region (quantum mechanical tunneling model) and decreases after 573 K (correlated barrier hopping model). Their dc activation energy was determined to be 0.51 eV and 0.62 eV, respectively. High dielectric permittivity ( \(\:{\epsilon\:}_{r}^{{\prime\:}}\) ) ~ 9458 and low dielectric loss ( \(\:\delta\:\) ) ~ 0.308 were observed at 308 K and frequency 100 Hz, and both values increase with the evolution of temperatures and quantify a higher ability to store the electrical charges in an electric field. The dielectric relaxations at various temperatures are associated with the Maxwell-Wagner (MW) type polarization, and the distribution of relaxation behavior or Cole-Cole parameter (α) divulged a non-ideal Debye type broader and symmetric distribution with temperatures. The modulus spectra help us to comprehend the origin of the giant dielectric constant and strong interfacial polarization by highlighting the grain and grain boundary contributions. The high dielectric constant, low loss, and high temperature stability recommend its promising applications in several electronic, energy, and sensing applications. Physical sciences/Materials science Physical sciences/Nanoscience and technology Physical sciences/Physics Complex double perovskite Impedance spectroscopy Giant dielectric constant AC conductivity polarons hopping mechanism Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 02 Feb, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 03 Dec, 2025 Reviews received at journal 01 Dec, 2025 Reviews received at journal 23 Nov, 2025 Reviewers agreed at journal 20 Nov, 2025 Reviewers agreed at journal 14 Nov, 2025 Reviewers invited by journal 14 Nov, 2025 Editor assigned by journal 05 Nov, 2025 Submission checks completed at journal 05 Nov, 2025 First submitted to journal 03 Nov, 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-8017034","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":542380390,"identity":"da7b3036-d9ab-41e7-a6d3-8e95ed206c59","order_by":0,"name":"Subrata Karmakar","email":"data:image/png;base64,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","orcid":"","institution":"Manipal University Jaipur","correspondingAuthor":true,"prefix":"","firstName":"Subrata","middleName":"","lastName":"Karmakar","suffix":""},{"id":542380391,"identity":"bf6e0336-5b2c-42ca-b2e1-ff14ca2ab47b","order_by":1,"name":"K. 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CaCu\u003csub\u003e3\u003c/sub\u003eTi\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e12\u003c/sub\u003e for extreme environment energy storage applications\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Complex double perovskite, Impedance spectroscopy, Giant dielectric constant, AC conductivity, polarons hopping mechanism","lastPublishedDoi":"10.21203/rs.3.rs-8017034/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8017034/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWe have synthesized CaCu\u003csub\u003e3\u003c/sub\u003eTi\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e12\u003c/sub\u003e using a green synthesis route, employing an oxalate precursor obtained from a mixture of Averrhoa carambola (star fruit) fruit juice and aloe vera extract. The structural, microstructural, and ac electrical transport characteristics of this material were examined at high temperatures from 308 K to 773 K and in a wide frequency window of 100 Hz to 1 MHz. The Rietveld refinement of X-ray diffraction (XRD) and Raman spectroscopy demonstrates the single-phase body-centered cubic crystal structure with space group \u003cem\u003eIm-3\u003c/em\u003e and \u003cem\u003eA\u003c/em\u003e\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eF\u003c/em\u003e\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e vibrational modes due to rotations of TiO\u003csub\u003e6\u003c/sub\u003e octahedral and Ti-O-Ti anti-stretching vibrations of CaCu\u003csub\u003e3\u003c/sub\u003eTi\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e12\u003c/sub\u003e. The fitted Nyquist plots (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Z}^{{\\prime\\:}}\\text{v}\\text{s}.\\:Z{\\prime\\:}{\\prime\\:})\\)\u003c/span\u003e\u003c/span\u003e at different temperatures exhibit the grain and grain boundary contributions, and the semicircles shrink at higher temperatures, which disclosed the negative temperature coefficient of resistance (NTCR) behavior. Both grain (\u003cem\u003eR\u003c/em\u003e\u003csub\u003e\u003cem\u003eg\u003c/em\u003e\u003c/sub\u003e) and grain boundary resistance (\u003cem\u003eR\u003c/em\u003e\u003csub\u003e\u003cem\u003egb\u003c/em\u003e\u003c/sub\u003e) and capacitances (C\u003csub\u003eg\u003c/sub\u003e, C\u003csub\u003egb\u003c/sub\u003e) diminished with temperature, and their activation energy was estimated to be ~\u0026thinsp;0.56 eV and ~\u0026thinsp;0.84 eV, respectively. The ac electrical conductivity increases with frequency and temperature due to thermally activated charge carriers, and the frequency exponent (\u003cem\u003en\u003c/em\u003e) remains nearly constant at low temperature region (quantum mechanical tunneling model) and decreases after 573 K (correlated barrier hopping model). Their dc activation energy was determined to be 0.51 eV and 0.62 eV, respectively. High dielectric permittivity (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\epsilon\\:}_{r}^{{\\prime\\:}}\\)\u003c/span\u003e\u003c/span\u003e)\u0026thinsp;~\u0026thinsp;9458 and low dielectric loss (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\delta\\:\\)\u003c/span\u003e\u003c/span\u003e)\u0026thinsp;~\u0026thinsp;0.308 were observed at 308 K and frequency 100 Hz, and both values increase with the evolution of temperatures and quantify a higher ability to store the electrical charges in an electric field. The dielectric relaxations at various temperatures are associated with the Maxwell-Wagner (MW) type polarization, and the distribution of relaxation behavior or Cole-Cole parameter (α) divulged a non-ideal Debye type broader and symmetric distribution with temperatures. The modulus spectra help us to comprehend the origin of the giant dielectric constant and strong interfacial polarization by highlighting the grain and grain boundary contributions. The high dielectric constant, low loss, and high temperature stability recommend its promising applications in several electronic, energy, and sensing applications.\u003c/p\u003e","manuscriptTitle":"Origin of giant dielectric permittivity and localized polarons supported electrical conduction in CaCu3Ti4O12 for extreme environment energy storage applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-11 16:24:49","doi":"10.21203/rs.3.rs-8017034/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-03T15:33:02+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-02T00:34:49+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-23T18:06:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"276677393439131878953219891195670025340","date":"2025-11-20T17:07:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"267939737691192852853614912221425884310","date":"2025-11-14T15:12:53+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-14T09:12:01+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-05T08:29:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-05T08:29:02+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-11-03T08:52:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"acd7b203-2dd1-457b-811f-fe30681ba8e8","owner":[],"postedDate":"November 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":57813220,"name":"Physical sciences/Materials science"},{"id":57813221,"name":"Physical sciences/Nanoscience and technology"},{"id":57813222,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-02-09T16:03:53+00:00","versionOfRecord":{"articleIdentity":"rs-8017034","link":"https://doi.org/10.1038/s41598-026-36234-6","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-02-02 15:58:48","publishedOnDateReadable":"February 2nd, 2026"},"versionCreatedAt":"2025-11-11 16:24:49","video":"","vorDoi":"10.1038/s41598-026-36234-6","vorDoiUrl":"https://doi.org/10.1038/s41598-026-36234-6","workflowStages":[]},"version":"v1","identity":"rs-8017034","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8017034","identity":"rs-8017034","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}