Defect induced polarization and dielectic relaxation in Ga$_2$$_-$$_x$Fe$_x$O$_3$

TL;DR

This study investigates dielectric and pyroelectric properties of Ga$_{2-x}$Fe$_x$O$_3$ solid solutions, revealing defect-related polarization and multiglass behavior due to dipolar clusters and relaxations.

Contribution

It demonstrates that the observed polarization arises from defect dipoles and TSDC effects, not intrinsic ferroelectricity, highlighting defect-induced phenomena in these materials.

Findings

Presence of dipolar cluster glass and spin glass behavior.

Identification of two dielectric relaxation processes.

Polarization mainly due to defect dipoles and TSDC effects.

Abstract

We report results of the dielectric and pyroelectric measurements on solid solutions of Ga$_2$$_-$$_x$Fe$_x$O$_3$ with x = 0.75, 1.0 and 1.25. These systems exhibit dipolar cluster glass behavior in addition to the spin glass behavior making them belong to a class of few systems showing multiglass behavior. Presence of two contributing relaxations in dielectric data are observed possibly due to the flipping and breathing of polar nano-clusters. Further, emergence of polarization in these systems can be understood in terms of thermally stimulated depolarization current (TSDC) effect caused by defect dipoles possibly associated with charged oxygen vacancies rather than the intrinsic ferroelectric behavior.