Abstract
In this work, we used CoxFe80-xB20 (x 60, 40, 20) as spin-polarizing layers (SPLs) in order to investigate the composition of the CoFeB-SPL on the magnetoresistance in Co/Pd multilayers-based pseudo-spin-valves (PSVs) with perpendicular magnetic anisotropy (PMA). In both soft layer and hard layer, the PMA was achieved by tuning the interface anisotropy and bulk anisotropy between SPL and Co/Pd multilayers. For all the films, giant magnetoresistance (GMR) was found to decrease with increasing SPL thickness in the as-deposited case, irrespective of the CoFeB atomic composition and saturation magnetization (M-s). However, interesting behavior is observed when the films were post annealed. Although GMR degradation is expected after annealing, a peak of GMR was observed after post annealing the samples at 250 degrees C. This peak is stronger for the samples with thicker SPLs than those with thinner SPLs. Nonetheless, further increase in annealing temperature causes a reduction in GMR which is found to be larger in Co rich atomic composition samples with a lower M-s. In the case of thicker CoFeB SPL (15 angstrom), the magnetization of overall composite (Co/Pd)/CoFeB soft layer appears to be canted from out of plane direction. Among the three compositions investigated, Co60Fe20B20 polarizer shows a stronger PMA due to its lower M-s, leading to the weaker demagnetizing field. In addition, this study also indicates that the crystallographic texture of Co/Pd multilayers plays a role in GMR of PSV stack structures. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773336]