[13p-P8-1~46] 10 スピントロニクス・マグネティクス(ポスター)

▼ [13p-P8-13] Spacer layer insertion effect on magnetic properties of Cr₂O₃/Co exchange coupling system

〇Tomohiro Nozaki¹、Satya Prakash Pati¹、Tatsuo Shibata²、Shougo Yonemura²、Tetsuya Nakamura³、Yoshinori Kotani³、Muftah K O Al-Mahdawi¹、Shujun Ye¹、Yohei Shiokawa¹、Masashi Sahashi^1,4 (1.Tohoku Univ.、2.TDK corporation、3.JASRI、4.ImPACT program)

キーワード：perpendicular exchange bias, spacer layer, magnetoelectric effect

Magnetoelectric material Cr₂O₃ has received much attentions as a promising candidate for voltage-controlled spin devices. We have demonstrated the voltage control of perpendicular exchange bias in Cr₂O₃/Co all thin film system [1,2], which make the practical applications more realistic. In these reports, it was essential to reduce the magnitude of exchange bias (H_ex) by inserting metal spacer layer such as Pt and Cr between Cr₂O₃ and Co to achieve the voltage-control of perpendicular exchange bias. It is noted that the role of metal spacer layers are not only reduce the magnitude of H_ex by make “space” between Cr₂O₃ and Co. The spacer layers largely affect to the magnetic properties of Co. In this study, we investigated the spacer layer effect on H_ex and magnetic properties of Co.
We use three metals, Pt, Ru, and Cr, for spacer layer. The sample structure is Al₂O₃ sub./Pt 25/Cr₂O₃ 250/spacer/Co 1/Pt 5(nm). Figure 1 shows the typical magnetization curve with different spacer layers. Obviously, the magnetic anisotropy differ according to the spacer materials. In additions, difference in magnetization was clearly observed. The spin polarization of Pt spacer or cap layer partly contribute to the results. We will discuss the difference based on the X-ray magnetic circular dichroism (XMCD) results of Co.
This work was partly funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Japan Government).
[1] T. Ashida et al., Appl. Phys. Lett., 104 (2014) 152409.
[2] T. Ashida et al., Appl. Phys. Lett., 106 (2015) 132407.