Sign of inverse spin Hall voltages generated by ferromagnetic resonance   and temperature gradients in yttrium iron garnet|platinum bilayers
  We carried out a concerted effort to determine the absolute sign of the inverse spin Hall effect voltage generated by spin currents injected into a normal metal. We focus on yttrium iron garnet (YIG)|platinum bilayers at room temperature, generating spin currents by microwaves and temperature gradients. We find consistent results for different samples and measurement setups that agree with theory. We suggest a right-hand-rule to define a positive spin Hall angle corresponding to with the voltage expected for the simple case of scattering of free electrons from repulsive Coulomb charges. 
Michael Schreier, Gerrit E. W. Bauer, Vitaliy Vasyuchka, Joost Flipse,   Ken-ichi Uchida, Johannes Lotze, Viktor Lauer, Andr...
cond-mat.mtrl-sci cond-mat.mes-hall