講演情報
[14p-K302-11]Tunneling magnetoresistance and spin-orbit torque magnetization switching in ferrimagnetic Gd-Fe-Co based magnetic tunnel junction
〇(D)Masahiko Yunokizaki1, Yuki Hibino2, Hiroshi Idzuchi1,3, Hanshen Tsai1, Mio Ishibashi1, Shinji Miwa3,4, Masamistu Hayashi1,4, Satoru Nakatsuji1,3,4,5 (1.Dep. Phys., Univ. Tokyo, 2.AIST, 3.ISSP, Univ. Tokyo, 4.TSQS, Univ. Tokyo, 5.JHU)
キーワード：
ferrimagnetic materials、Tunneling magnetoresistance、Spin-orbit torque magnetization switching
This presentation discusses the development of magnetoresistive random-access memory (MRAM) using magnetic tunnel junctions (MTJs), which has been commercialized. Current research aims to enhance the speed of these devices by replacing the ferromagnetic layers with antiferromagnetic and ferrimagnetic materials. Recent advancements in the 180° switching of magnetic moments in antiferromagnets show promise for MTJ development, while ferrimagnets, especially near their magnetization compensation point, also offer fast spin dynamics for high-speed operations. However, few studies focus on MTJs with ferrimagnets.The presentation details an investigation into spin-orbit torque magnetization switching in three-terminal MTJs with a ferrimagnetic Gd-Fe-Co free layer. The research uses Pt for spin current generation and a Co-Fe-B synthetic antiferromagnet as the reference layer, with a thin Fe-B layer placed between the Gd-Fe-Co free layer and the MgO barrier. The study finds that increasing the thickness of the Fe-B layer from 0.4 to 1.2 nm enhances the tunnel magnetoresistance ratio, which saturates at around 14%. Meanwhile, the current density required to reverse the magnetization via spin-orbit torque remains almost constant. These findings demonstrate the effectiveness of the thin Fe-B layer in achieving substantial tunneling magnetoresistance and efficient spin-orbit torque switching.