Identification of transverse spin currents in noncollinear magnetic   structures
  We show that the transverse components of spin current in a ferromagnet is linked to an off diagonal spin component of the transmission matrix at interfaces;it has little to do with the mismatch of band structures between dissimilar metals. When we take account of this component,not considered in prior analyses, we find spin torque comes from a region of at lease 3 nm around an interface. 
Jianwei Zhang, Peter M Levy, Shufeng Zhang, Vladimir Antropov