Dielectric behavior of hexagonal and orthorhombic YFeO3 prepared by modified sol-gel method

Polycrystalline YFeO3 ceramic powders were synthesized by modified polyacrylamide sol-gel method. X-ray diffraction analysis demonstrated that the crystal structures of YFeO3 could be controlled from hexagonal phase (h-YFeO3) to orthorhombic phase (o-YFeO3) through the calcined temperature. Temperature-dependent dielectric constants (epsilon(r)) and losses (tan delta) show that strong frequency dispersion phenomena occur in wholemeasuring temperature. Both the h-YFeO3 and o-YFeO3 exhibit dielectric relaxation behavior at T < 250 K and at T > 340 K, which could be attributed to thermal activation. Whereas, only h-YFeO3 shows an anomaly dielectric peak at T-m = 297 K fitted with Curie-Weiss law and modified Curie-Weiss law, indicating a possible P6 (3)mc-P6 (3)cm transition with slightly diffuse characteristics.