Influence of Spin Polarizer on the Magnetoresistance, Switching Property, and Interlayer Interactions in Co/Pd Single Spin Valves

In order to investigate the effect of polarization and saturation magnetization (M_S) in Co/Pd multilayers-based pseudo-spin valve (PSV) structures with perpendicular magnetic anisotropy (PMA), we studied different spin polarizer layers (SPL). The PMA could be achieved by tuning the thickness and M_s of the SPL. Sharp switching of magnetization for both soft layer (SL) and hard layer (HL) were observed for all studied structures with thin SPL, indicating higher PMA in the film structures. However, interesting behavior was observed for thicker SPLs where a tail in hysteresis loop was observed. For further understanding of the interactions in multilayers we have carried out first-order reversal curve (FORC) measurements. The FORC contours pointed out the correlation between exchange interactions with magnetostatic interaction and minor loop shifts in hysteresis curves. Giant magnetoresistance (GMR) was observed for the PSV films with thick Co₆₅Fe₃₅ (10 Å and 15 Å) SPL. However, GMR value as a function of thickness decreases for all the other films with different M_s. Moreover, we have clarified that GMR is correlated to the fcc (111) orientation of Co/Pd multialyers. The maximum value of GMR with largest M_s shows the minimum value of full width at half maximum (FWHM) for fcc (111) peak, indicating that the large GMR as well as high PMA occurs for the samples deposited in good fcc (111) texture.