Modulation of thermal stability and spin-orbit torque in IrMn/CoFeB/MgO structures through atom thick W insertion

Danrong Xiong, Shouzhong Peng, Jiaqi Lu, Weixiang Li, Hao Wu, Zhi Li, Houyi Cheng, Yuyan Wang, Christian H. Back, Kang L. Wang, Weisheng Zhao

Research output: Contribution to journalArticlepeer-review

Abstract

Antiferromagnet (AFM)/ferromagnet (FM) systems such as IrMn/CoFeB/MgO enable spin-orbit-torque- (SOT-) induced switching of perpendicular magnetization in the absence of an external magnetic field. However, the low thermal stability, weak perpendicular magnetic anisotropy (PMA), and indistinctive SOT of these AFM/FM heterostructures pose challenges to the practical application. Here, through the insertion of a thin W layer between the IrMn and CoFeB layers, we show that much larger effective PMA fields are obtained with annealing stability to 300 °C, which is guaranteed by the prevention of Mn diffusion via W insertion as shown in spherical aberration corrected transmission electron microscopy and atomic-resolution electron energy-loss spectroscopy measurement results. Furthermore, the spin-orbit torque is effectively tuned by changing the W layer thickness via modulation of the interfacial spin-orbit coupling at IrMn/W/CoFeB interfaces, which was reported to degrade the interface spin transparency for the spin currents. Finally, field-free magnetization switching was achieved with comparable exchange bias fields to samples without W insertion. This work demonstrates an effective strategy for improving the performance of the thermally robust AFM-based SOT device.

Original languageEnglish
Article number29522
JournalApplied Physics Letters
Volume117
Issue number21
DOIs
Publication statusPublished - 2020 Nov 23

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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