Angular momentum transfer torques in spin valves with perpendicular   magnetization
  Spin valves incorporating perpendicularly magnetized materials are promising structures for memory elements and high-frequency generators. We report the angular dependence of the spin-transfer torque in spin valves with perpendicular equilibrium magnetization computed by first-principles circuit theory and compare results with experiments by W.H. Rippard c.s. [Phys. Rev. B 81, 014426 (2010)] on the CoFe|Cu|CoNi system. Furthermore, we predict a non-monotonous ("wavy") spin-transfer torque when the Cu spacer is replaced by a Ru layer. 
Xingtao Jia, Ying Li, Ke Xia, and Gerrit E. W. Bauer
cond-mat.mes-hall cond-mat.mtrl-sci