Journal Article

Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields

Tserkovnyak, Yaroslav, Lang, Murong, Tang, Jianshi, Yu, Guoqiang, Takei, So, Amiri, Pedram Khalili, Bender, Scott A., Wong, Kin L., Wang, Yong, Alzate, Juan G., Chang, Li-Te, Jiang, Ying, Jiang, Wanjun, Wang, Kang L., Fan, Yabin, Upadhyaya, Pramey

2014

Overview

Magnetization switching by current-induced spin–orbit torques is of great interest due to its potential applications in ultralow-power memory and logic devices. The switching of ferromagnets with perpendicular magnetization is of particular technological relevance. However, in such materials, the presence of an in-plane external magnetic field is typically required to assist spin–orbit torque-driven switching and this is an obstacle for practical applications. Here, we report the switching of out-of-plane magnetized Ta/Co 20 Fe 60 B 20 /TaO x structures by spin–orbit torques driven by in-plane currents, without the need for any external magnetic fields. This is achieved by introducing a lateral structural asymmetry into our devices, which gives rise to a new field-like spin–orbit torque when in-plane current flows in these structures. The direction of the current-induced effective field corresponding to this field-like spin–orbit torque is out-of-plane, facilitating the switching of perpendicular magnets. Spin–orbit torques in a geometrically asymmetric device made from a perpendicularly magnetized ferromagnet can switch its magnetization without the assistance of an applied magnetic field.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 140/146 / 142/126 / 147/143 / 639/766/119/1001 / Asymmetry / Electrons / Ferromagnetism / Magnetic fields / Magnetization / Materials Science / Memory devices / Nanotechnology / Nanotechnology and Microengineering / Oxidation / Random access memory / Switching / Symmetry / Torque