Magnetoresistance and thermal stability enhancement in FeCr-based spin valves

Abstract

In a synthetic spin valve (SV), a thin FeCr layer inserted in the pinned layer closer to the antiferromagnetic layer was found to improve the magnetoresistance, the pinning field strength, and thermal stability. Single SVs with 1-nm-thick FeCr inserted in the pinned layer shows a magnetoresistance ratio (MR) of 18% and a pinned field of about 1700Oe. This letter reports on the high MR in an all-metal single SV without specular scattering using a nano-oxide layer or spin filtering. This result, suggests that FeCr with high resistance and low spin polarization is effective in increasing the spin scattering and maximize the contribution of the pinned layer closer to spacer on the magnetotransport while keeping its antiferromagnetic exchange coupling high. The FeCr thin layer may also have an effect on minimizing Mn diffusion into the pinned layer and spacer as revealed by the increase of the pinning field.