Spin–orbit torques in structures with asymmetric dusting layers
Abstract
Current-induced spin–orbit torques (SOTs) in heavy metal/ferromagnet heterostructures have emerged as an efficient method for magnetization switching with applications in nonvolatile magnetic memory and logic devices. However, experimental realization of SOT switching of perpendicular magnetization requires an additional inversion symmetry breaking, calling for modifications of the conventional SOT heterostructures. In this work, we study SOTs and deterministic switching of perpendicular magnetization by inserting different asymmetric dusting layers at the heavy metal/ferromagnet interface. Similar to the previous works with lateral structural asymmetry, we study the emergence of current-induced perpendicular effective magnetic fields (Hzeff). By examining three different material combinations of heavy metal/dusting layers (W/IrMn, Pt/IrMn, and W/Ta), we shed light on the origins of Hzeff; we show that Hzeff is generically created in all the studied asymmetric structures, has a close correlation with the interfacial magnetic anisotropy, and is independent of the signs of spin Hall angles of the materials. Furthermore, we show that the induction of Hzeff enables field-free deterministic SOT switching of perpendicular magnetization. Our results can be used in designing SOT heterostructures for practical applications in nonvolatile technologies.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 02, 2020
- Source ID
- 10.1063/5.0029347
Entities
People
- Bingqian Dai
- Di Wu
- Guoqiang Yu
- Hao Wu
- Haoran He
- K. C. Wong
- Kang L. Wang
- Kin Wong
- Seyed Armin Razavi
Organizations
- Beijing Municipal Natural Science Foundation
- Institute of Physics
- National Natural Science Foundation of China
- National Science Foundation
- United States Department of Energy
- University of California