Huge giant-magnetoresistance of Co/Ru/L11-CoPt multi-layer pseudo-spin valve

Co/Ru/L11-CoPt based thin film as pseudo spin valve prepared by DC magnetron sputtering deposition. The magnetic and magnetoresistance properties with the thickness change of L11-CoPt layer were investigated. The resulting spin valve exhibited well-different out-of-plane and in-plane hysteresis loops. The coercivities changed unpredictably at different thicknesses of L11-CoPt layer. A perpendicular giant magnetoresistance ratio is obtained about 59.70 % and 160 % with current-out-of-plane measurements for the pattern and cross-linking structures of Pt(20 nm)/Co(2.5 nm)/Ru(1.5 nm)/[L11-CoPt]8/Pt(20 nm)/glass substrate, respectively. It was ascribed this giant magnetoresistance to spin-dependent transmission of the conduction electrons between Co free layer and L11-CoPt reference layer through Ru spacer layer, and considered as the ferromagnetic interlayer exchange coupling.