Enhanced magnetic and dielectric properties of Ti-doped YFeO3 ceramics

Polycrystalline YFeO3 (YFO) and YFe1-(4/3)xTixO3(YFTO) ceramics were prepared using the powder synthesized from the sol-gel route. X-ray diffraction analyses of the polycrystalline ceramics revealed the crystallization of the phase in orthorhombic crystal structure associated with the space group Pnma. The magnetization versus magnetic field hysteresis loops were obtained at room temperature for YFO and YFTO ceramics. The magnetic property changes from weak ferromagnetic in YFO to ferromagnetic in YFTO ceramics. The dielectric constant recorded at room temperature for YFTO ceramics was six times higher than that of YFO, whereas the dielectric loss gets reduced to 0.06 from 0.3 for YFO at 1kHz. Impedance spectroscopy study carried out on YFO and YFTO ceramics confirmed the existence of non-Debye-type relaxation. Observed single semicircle in Z vs -Z plot established the incidence of intrinsic (bulk) effect and ruled out any grain boundary or electrode effects. The mechanism for the dielectric relaxation and electrical conduction process observed in YFO and YFTO ceramics was discussed by invoking electric modulus formalisms. Activation energy obtained by ac conductivity study suggested that the conduction process in YFO was linked up with the existence of the polaron and oxygen vacancies, whereas only oxygen vacancies contribute to the conduction process in YFTO ceramics.