[14a-2J-1~12] 10.3 Giant magnetoresistance (GMR), tunnel magnetoresistance (TMR) and magnetic recording technologies

▲ [14a-2J-7] Voltage-induced magnetic anisotropy change of Fe-4f-metal alloys

〇(M2)Kazuhito Tanaka¹, Shinji Miwa¹, Norikazu Mizuochi¹, Yoshishige Suzuki¹ (1.Osaka Univ.)

Keywords:TMR,voltage effect,MTJ

Voltage-induced magnetic anisotropy change has been investigated because of its potential for non-volatile magnetic random access memories with low power operation. [1,2] Since spin-orbit coupling plays an important role in the voltage-induced anisotropy change, in our previous study, we tested 4f-metals since 4f metals have large orbital moment. In FeGd alloys, large anisotropy field change and magnetization-energy change ratio have been observed [3]. This suggests that 4f-metals are promising for voltage-induced spintronics devices. In this study, we investigated voltage-inducecd anisotropy change of FeTb(Nd)|MgO|-based magnetic tunnel junctions (MTJs).
V (30 nm)|Fe_100-x(Gd_x, Tb_x Nd_x) [x = 0-30]|MgO (1.6 nm)|Fe (10 nm) multilayer was fabricated by molecular beam epitaxy method on MgO [001] substrate as shown in Fig. 1. The Fe-4f metal alloy layer was prepared using co-evaporation of pure Fe and 4f metals. The film was patterned into MTJs by using electron-beam lithography and an Ar ion-milling. Fig. 2 shows the normalized magnetization curve of Fe (0.55 nm), Fe₉₀Gd₁₀ (0.60 nm) and Fe₉₀Tb₁₀ (0.64 nm) at 0.3 V (-0.3 V), which is calculated by magnetization curve. From this, the anisotropy field changes of Fe₉₀Gd₁₀ and Fe₉₀Tb₁₀ are larger than that of Fe.
This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan)