Dielectric relaxation and ac conductivity in magnetoelectric YCrO3 ceramics: A temperature dependent impedance spectroscopy analysis

摘要

Here, we report on the temperature and frequency dependent electrical conduction and dielectric behaviour of YCrO3 ceramics. Dielectric studies reveal a peak in the dielectric constant similar to 230 K, suggesting presence of spin-charge coupling. Also, an additional broad peak found at similar to 450 K is reminiscent of a relaxor like behaviour for YCrO3, attributed to a diffused phase transition. The nature of dc conductivity is of Arrhenius type and shows an abrupt change in the activation energy at similar to 230 K and similar to 450 K. The activation energy suggests that the polaronic hopping mechanism stabilizes at low temperature while, at higher temperatures, the process is associated with the diffusion of double ionized oxygen vacancies. However, ac conductivity suggests that the overlapping large polaron tunnelling conduction mechanism drives the ac conduction below 300 K and above 300 K, the conduction behaviour is consistent with the correlated barrier hopping conduction mechanism.