Low damping insertion elements for the exchange coupled hard/soft composite structure

Abstract

We have experimentally investigated the effect of V and Zr insertion thickness on perpendicular magnetic anisotropy (PMA) in [Co/Pt multilayers]/[Zr, V]/CoFeB (Hard/Soft) composite structures. Micromagnetic simulations have been performed to study the effect of the Gilbert damping constant on the switching characteristics in a hard/soft composite structure for weak and strong interlayer exchange coupling. The V and Zr insertions are studied due to their low Gilbert damping constant with the CoFeB interface. For both insertions, the interlayer exchange coupling remained ferromagnetic in nature for all the thicknesses studied. We observed an increase in PMA with increasing V and Zr insertion thicknesses. The composite layer with V insertion provides thermal stability comparable to the previously reported Ta insertion. From micromagnetic simulations, we observed that the effect of the Gilbert damping constant on switching characteristics is largest for thinner insertions (strong ferromagnetic coupling) and the effect diminishes with increasing insertion thickness (weak ferromagnetic coupling).