Interlayer magnetostatic coupling induced Co layer coercivity enhancement and exchange bias in [Pd/Co]/Cu/Co spin valves

Abstract

Interlayer stray field coupling in hybrid perpendicular/Cu/in-plane magnetic anisotropy [Pd/Co]/Cu/Co single spin valves and [Pd/Co]/Cu/Co/Cu/[Co/Pd] dual spin valves was investigated. Enhancements of Co layer coercivity were observed after ac or dc demagnetization of the samples. This effect originates from the pinning of Co domain walls by the in-plane stray field from Co/Pd stripe domains, and the enhancements are more efficient as the Co/Pd domain size decreases. Moreover, the magnetostatic interaction between the net in-plane Co/Pd remanent moments and the Co moments leads to exchange bias in the Co layer of the dual spin valve after the dc demagnetization.