Method and system for providing a stable spin filter

A method and system for providing a spin filter is disclosed. The method and system include providing a pinned layer, a free layer, and a conductive nonmagnetic spacer layer between the pinned layer and the free layer. The method and system also include providing a spin filter layer and a capping layer on the spin filter layer. The spin filter layer is adjacent to the free layer. The spin filter layer is on an opposite side of the free layer as the nonmagnetic spacer layer and includes at least Pt and/or Rh. The capping layer has a specular reflection layer therein. In one aspect, the specular reflection layer allows specular reflection of current carriers traveling from the spin filter layer to the specular reflection layer. In another aspect, the specular reflection layer includes at least Ta, Ti, Zr, Hf, Nb, Al, Mo, W, Si, Cr, V, Ni, Co, and Fe.