Temperature and frequency dependence of dielectric relaxations in YFeO3

Abstract

We report a dielectric study in wide frequency and temperature ranges of yttrium orthoferrite, YFeO3, in order to obtain the temperature-frequency dependence of the dielectric relaxation processes. A mixture of oxide powders (Y2O3 and Fe2O3) was activated by high-energy ball milling. The mechanically activated powders were pressed and sintered at 1073 K. The cylindrical test samples were characterized at room temperature by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Broadband Dielectric Spectroscopy (BDS) studies were carried out at several temperatures to the best understanding of dielectric properties. The X-ray diffraction patterns show an orthorhombic YFeO3 single phase. The magnetic hysteresis loop shows a weak ferromagnetic behavior, characteristic of the YFeO3. Dielectric spectroscopy analysis allows identifying two relaxation processes, the first at temperatures between 193 and 253 K and second above 333 K, defined as low-temperature dielectric relaxation (LTDR) and high-temperature dielectric relaxation (HTDR), respectively. It was determined the activation around 0.4 eV and 1.0 eV for the LTDR and HTDR, respectively. It indicates a single and doubly ionized oxygen vacancy. Moreover, it was proved that a hopping model is the dominating mechanism in the studied material, due to the conduction mechanism follows the Jonscher power law.