We test whether current-induced magnetization switching due to spin-transfer-torque in ferromagnetic/non-magnetic/ferromagnetic (F/N/F) trilayers changes significantly when scattering within the N-metal layers is changed from ballistic to diffusive. Here ballistic corresponds to a ratio r = λ/t = 3 for a Cu spacer layer, and diffusive to r = 0.4 for a CuGe alloy spacer layer, where λ is the mean-free-path in the N-layer of fixed thickness t = 10 nm. The average switching currents for the alloy spacer layer are only modestly larger than those for Cu. The best available model predicts a much greater sensitivity of the switching currents to diffuse scattering in the spacer layer than we see.
Citation: Physical Review B (Condensed Matter and Materials Physics)
Pub Type: Journals
ballistic transport, Boltzmann equation, current-induced magnetization, diffusive transport, nanopillar, spin-transfer torque, spin-valve