Interfacial exchange coupling and magnetization reversal in perpendicular [Co/Ni]_N/TbCo composite structures

摘要

Interfacial exchange coupling and magnetization reversal characteristics in the perpendicular heterostructures consisting of an amorphous ferrimagnetic (FI) Tb _x Co_{100– x} alloy layer exchange-coupled with a ferromagnetic (FM) [Co/Ni]_N multilayer have been investigated. As compared with pure Tb _x Co_{100– x} alloy, the magnetization compensation composition of the heterostructures shift to a higher Tb content, implying Co/Ni also serves to compensate the Tb moment in TbCo layer. The net magnetization switching field H _c⊥ and interlayer interfacial coupling field H _ex, are not only sensitive to the magnetization and thickness of the switched Tb _x Co_{100– x} or [Co/Ni]_N layer, but also to the perpendicular magnetic anisotropy strength of the pinning layer. By tuning the layer structure we achieve simultaneously both large H _c⊥?=?1.31?T and H _ex?=?2.19?T. These results, in addition to the fundamental interest, are important to understanding of the interfacial coupling interaction in the FM/FI heterostructures, which could offer the guiding of potential applications in heat-assisted magnetic recording or all-optical switching recording technique.