Phase-sensitive detection of spin pumping via the ac inverse spin Hall effect.
We use a phase-sensitive, quantitative technique to separate inductive and ac inverse spin Hall effect (ISHE) voltages observed in Ni(81)Fe(19)/normal metal multilayers under the condition of ferromagnetic resonance. For Ni(81)Fe(19)/Pt thin film bilayers and at microwave frequencies from 7 to 20 GHz, we observe an ac ISHE magnitude that is much larger than that expected from the dc spin Hall angle Θ(SH)(Pt) = 0.1. Furthermore, at these frequencies, we find an unexpected, ≈ 110° phase of the ac ISHE signal relative to the in-plane component of the resonant magnetization precession. We attribute our findings to a dominant intrinsic ac ISHE in Pt.
Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Mathias
M
Weiler
Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Justin M
JM
Shaw
Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Hans T
HT
Nembach
Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Thomas J
TJ
Silva