Bulk and interfacial scatterings in current-perpendicular-to-plane giant magnetoresistance with Co2Fe(Al0.5Si0.5) Heusler alloy layers and Ag spacer

We report the transport properties of a current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) device with Co2Fe(Al0.5Si0.5) (CFAS) Heusler alloy ferromagnetic layers and a Ag spacer layer. The CPP-GMR devices showed relatively high Delta RA values and MR ratios up to 17 m Omega mu m(2) and 80% at 14 K, and 8 m Omega mu m(2) and 34% at 290 K. The spin diffusion length similar to 3 nm and the bulk spin asymmetry similar to 0.77 for the CFAS alloy at 14 K were estimated by the Valet-Fert model, indicating a large contribution of the interfacial scattering. (C) 2010 American Institute of Physics. [doi:10.1063/1.3432070]