Spin glassy behavior and large exchange bias effect in cubic perovskite Ba0.8Sr0.2FeO3?δ

摘要

A single-phase iron oxide Ba0.8Sr0.2FeO3?δ with a simple cubic perovskite structure in Pm-3m symmetry is success-fully synthesized by a solid-state reaction method in O2 fl ow. The oxygen content is determined to be about 2.81, indicating the formation of mixed Fe3+and Fe4+charge states with a disorder fashion. As a result, the compound shows small-polaron conductivity behavior, as well as spin glassy features arising from the competition between the ferromagnetic interaction and the antiferromagnetic interaction. Moreover, the competing interactions also give rise to a remarkable exchange bias effect in Ba0.8Sr0.2FeO2.81, providing an opportunity to use it in spin devices.