Magnetoelectric Induced Switching of Perpendicular Exchange Bias Using 30-nm-Thick Cr₂O₃ Thin Film

• Main Authors: Yu Shiratsuchi, Yiran Tao, Kentaro Toyoki, Ryoichi Nakatani
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Magnetochemistry
• Subjects: magnetoelectric effect; antiferromagnetism; Cr₂O₃ thin film; exchange bias
• Online Access: https://www.mdpi.com/2312-7481/7/3/36

Magnetoelectric (ME) effect is a result of the interplay between magnetism and electric field and now, it is regarded as a principle that can be applied to the technique of controlling the antiferromagnetic (AFM) domain state. The ME-controlled AFM domain state can be read out by the magnetization of the adjacent ferromagnetic layer coupled with the ME AFM layer via exchange bias. In this technique, the reduction in the ME layer thickness is an ongoing challenge. In this paper, we demonstrate the ME-induced switching of exchange bias polarity using the 30-nm thick ME Cr₂O₃ thin film. Two typical switching processes, the ME field cooling (MEFC) and isothermal modes, are both explored. The required ME field for the switching in the MEFC mode suggests that the ME susceptibility (α₃₃) is not deteriorated at 30 nm thickness regime. The isothermal change of the exchange bias shows the hysteresis with respect to the electric field, and there is an asymmetry of the switching field depending on the switching direction. The quantitative analysis of this asymmetry yields <i>α</i>₃₃ at 273 K of 3.7 ± 0.5 ps/m, which is comparable to the reported value for the bulk Cr₂O_3.