Hydrothermal Synthesis, Structural Characterization, Magnetic, Dielectric and Transport Properties of La2FeCrO6 Double Perovskites

A La2FeCrO6 (LFCO) double perovskite powders were synthesized by hydrothermal method, which crystallized in an orthorhombic (Pnma) structure and exhibited a spherical morphology with average particle size of 900 nm. Fourier transformation infrared spectroscopy confirmed the octahedral coordination of Fe and Cr ions in the powders. XPS spectra revealed dual oxide states of Fe (Fe2+/Fe3+) and Cr (Cr3+/Cr4+) elements, and oxygen element appeared as lattice oxygen and defect oxygen, respectively. The LFCO powders exhibit ferromagnetic behavior at 5 K with saturation magnetization of 0.31 μB/f.u., coercive field of 8.0 kOe, and Curie temperature of 200 K. Griffiths phase appeared in the powders between 200 K and 223 K. The LFCO ceramics displayed a butterfly-like magnetoresistance (MR)-magnetic field (H) curve at 5 K with MR (5 K, 6 T) value of -4.07%. Temperature dependence of resistivity of the LFCO ceramics demonstrated their semiconducting nature. Electrical transport data were fitted by different conduction models. Strong frequency dispersion dielectric behavior was observed in the LFCO ceramics. A dielectric abnormality observed around 260 K, was ascribed to the jumping of electrons trapped in shallow levels created by oxygen vacancies. The dielectric relaxation behavior exhibited by dielectric loss between 160 K and 260 K, was contributed to the singly-ionized oxygen vacancies.