Enhanced spin-orbit torques in Pt/Co/Ta heterostructures
Abstract
Spin-orbit torques (SOTs) are studied in perpendicularly magnetized ultrathin Co films sandwiched between two heavy metals, Pt and Ta. A significant enhancement of the Slonczewski-like torque is achieved by placing dissimilar metals with opposite spin Hall angles on opposite sides of the ferromagnet. SOTs were characterized through harmonic measurements and the contribution by the Ta overlayer was isolated by systematically varying its thickness. An effective spin Hall angle of up to 34% is observed, along with a sizable field-like torque that increases with increasing Ta layer thickness. Current-induced switching measurements reveal a corresponding increase in switching efficiency, suggesting that by engineering both interfaces in trilayer structures, the SOTs can be significantly improved.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 24, 2014
- Source ID
- 10.1063/1.4902529
Entities
People
- Aik Jun Tan
- Geoffrey S. D. Beach
- Lucas Caretta
- Maxwell Mann
- Seonghoon Woo
Organizations
- Defense Advanced Research Projects Agency
- Massachusetts Institute of Technology
- National Science Foundation
- Semiconductor Research Corporation