Perpendicular Magnetic Anisotropy in Amorphous Ferromagnetic CoSiB/Pt Multilayers

Abstract

Magnetic anisotropy properties of amorphous ferromagnetic CoSiB/Pt multilayers with perpendicular magnetic anisotropy (PMA, K-u) were systematically investigated as a function of CoSiB layer thickness (t(coSiB)) and Pt layer thickness (t(pt)). In two series of t(coSiB) /t(ocsiB)/Pt t(pt)](5) multilayers, the perpendicular coercivity (H-c) increased to reach a maximum and then decreased with further increase in both t(coSiB) and t(pt), due to intermixing of CoSiB/Pt interfaces. Particularly, using the amorphous soft magnetic CoSiB, the coercivity became very sensitive to the CoSiB thickness. These multilayer films exhibited a high Ku of 2 x 10(6) erg/cc and a high H-c of 360 Oe with marked squareness. It was found that even after annealing at 350 degrees C, the CoSiB/Pt multilayers had a high PMA and their Hc increased.