Current-perpendicular-to-plane giant magnetoresistance in half-metallic pseudo-spin-valve structures

Abstract

We have investigated the giant magnetoresistance (GMR) effect in Fe3 O4 Cu Ni80 Fe20 pseudo-spin-valve (PSV) structures for the current-perpendicular-to- plane (CPP) configuration. We observed drastic changes in the CPP GMR as the thickness of the Cu spacer layer, tCu, was varied. The GMR ratio decreases monotonically with increasing tCu, in good agreement with the Valet-Fert model in the long spin diffusion length limit. It was also observed that for a fixed tCu, GMR ratio increases with increasing Fe3 O4 layer thickness due to enhanced contributions from bulk scattering to the overall spin dependent scattering in the PSV structure. The CPP GMR ratio has strong temperature dependence and decreases monotonically with increasing temperature. © 2008 American Institute of Physics.