An Effective Reduction of Critical Current for Current-Induced   Magnetization Switching by a Ru Layer Insertion in an Exchange-Biased   Spin-Valve
  Recently it has been predicted that a spin-polarized electrical current perpendicular-to-plane (CPP) directly flowing through a magnetic element can induce magnetization switching through spin-momentum transfer. In this letter, the first observation of current-induced magnetization switching (CIMS) in exchange-biased spin-valves (ESPVs) at room temperature is reported. The ESPVs show the CIMS behavior under a sweeping dc current with a very high critical current density. It is demonstrated that a thin Ruthenium (Ru) layer inserted between a free layer and a top electrode effectively reduces the critical current densities for the CIMS. An "inverse" CIMS behavior is also observed when the thickness of the free layer increases. 
Y. Jiang, S.Abe, T.Ochiai, T.Nozaki, A.Hirohata, N.Tezuka and   K.Inomata