Quantification of the spin-Hall anti-damping torque with a resonance   spectrometer
  We present a simple technique using a cavity-based resonance spectrometer to quantify the anti-damping torque due to the spin Hall effect. Modification of ferromagnetic resonance is observed as a function of small DC current in sub-mm-wide strips of bilayers, consisting of magnetically soft FeGaB and strong spin-Hall metal Ta. From the detected current-induced linewidth change, we obtain an effective spin Hall angle of 0.08-0.09 independent of the magnetic layer thickness. Our results demonstrate that a sensitive resonance spectrometer can be a general tool to investigate spin Hall effects in various material systems, even those with vanishingly low conductivity and magnetoresistance. 
Satoru Emori, Tianxiang Nan, Trevor M. Oxholm, Carl T. Boone, John G.   Jones, Brandon M. Howe, Gail J. Brown, David E. Budi...
cond-mat.mtrl-sci cond-mat.mes-hall