Temperature and frequency dependence of dielectric relaxations in YFeO3

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.

Automated summary

The dielectric study of yttrium orthoferrite YFeO3 revealed temperature-frequency dependence of dielectric relaxation processes. The material exhibited orthorhombic crystal structure and weak ferromagnetic behavior. Two relaxation processes at different temperature ranges were identified, with activation energies corresponding to single and doubly ionized oxygen vacancies. The dominant conduction mechanism was found to follow the Jonscher power law, indicating a hopping model in the material.