Improvement of leakage, magnetic and magnetodielectric properties in cobalt doped gallium ferrite

Abstract

Gallium ferrite (GFO) is a magnetoelectric (ME) material, capturing growing attention due to its strong ME coupling at room temperature. However, the application of the material in practical use is hindered due to its high leakage. In this work, the effects of cobalt (Co) substitution at the iron (Fe) sites of GaFe1−x Co x O3 (0.0 ⩽ x ⩽ 0.1) polycrystals on the structure, electric and magnetic properties are investigated in detail. 5 at. wt.% substitution (x = 0.05) with cobalt ions achieves a reduction in leakage current density by four orders of magnitude due to reduced hopping between Fe3+ and Fe2+ ions and suppression of the oxygen vacancy formation. This is supported by higher dielectric constant and lower dielectric loss, as well as a significant difference between grain and grain boundary resistances. Two-phase-like magnetic behavior in magnetic hysteresis loop with enhanced magnetization and two magnetic transition temperatures are observed in the doped samples. All samples exhibited an increase in the magnetodielectric factor, indicating enhanced coupling between magnetic and electrical parameters. By concurrently increasing dielectric, magnetic, and coupling between them, this study describes a viable technique for lowering the most significant impediment to GFO’s usage as a ME device.