Absorption of transverse spin current in ferromagnetic NiCu: Dominance of bulk dephasing over spin-flip scattering
Abstract
In ferromagnetic metals, transverse spin currents are thought to be absorbed via dephasing—i.e., destructive interference of spins precessing about the strong exchange field. Yet, due to the ultrashort coherence length of ≈1 nm in typical ferromagnetic thin films, it is difficult to distinguish dephasing in the bulk from spin-flip scattering at the interface. Here, to assess which mechanism dominates, we examine transverse spin-current absorption in ferromagnetic NiCu alloy films with reduced exchange fields. We observe that the coherence length increases with decreasing Curie temperature, as weaker dephasing in the film bulk slows down spin absorption. Moreover, nonmagnetic Cu impurities do not diminish the efficiency of spin-transfer torque from the absorbed spin current. Our findings affirm that the transverse spin current is predominantly absorbed by dephasing inside the nanometer-thick ferromagnetic metals, even with high impurity contents.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 28, 2022
- Source ID
- 10.1063/5.0120865
Entities
People
- Christoph Klewe
- D. A. Smith
- Padraic Shafer
- Satoru Emori
- Shuang Wu
- Youngmin Lim
Organizations
- Advanced Light Source
- Air Force Office of Scientific Research
- Division of Materials Research
- United States Department of Energy
- Virginia Tech