Spin-scattering rates in metallic thin films measured by ferromagnetic resonance damping enhanced by spin-pumping

Published: June 12, 2015

Author(s)

Carl T. Boone, Justin M. Shaw, Hans T. Nembach, Thomas J. Silva

Abstract

We determined the spin-transport properties of Pd and Pt thin films by measuring the increase in ferromagnetic resonance damping due to spin-pumping in ferromagnetic (FM)-nonferromagnetic metal (NM) multilayers with varying NM thicknesses. The increase in damping with NM thickness depends strongly on both the spin- and charge-transport properties of the NM, as modeled by diffusion equations that include both momentum- and spin-scattering parameters. We use the analytical solution to the spin-diffusion equations to obtain spin-diffusion lengths for Pt and Pd. By measuring the dependence of conductivity on NM thickness, we correlate the charge- and spin-transport parameters, and validate the applicability of various models for momentum- scattering and spin-scattering rates in these systems: constant, inverse-proportional (Dyakanov-Perel), and linear-proportional (Elliot-Yafet). We confirm previous reports that the spin-scattering time appears to be shorter than the momentum scattering time in Pt, and the Dyakanov-Perel-like model is the best fit to the data.
Citation: Journal of Applied Physics
Volume: 117
Issue: 22
Pub Type: Journals

Keywords

spintronics, spin-pumping, spin-diffusion, ferromagnetic resonance, damping, Landau- Lifshitz, platinum, paladium
Created June 12, 2015, Updated November 10, 2018