Structure & magnetic properties of Cr/SmCo₅/Pt/CoFeB multilayer thin films

The structural and magnetic properties of exchange spring magnetic Cr/SmCo₅/Pt/CoFeB multilayer thin films deposited by ion beam sputtering have been explored. X-ray reflectivity analysis reveals the sharp layered structure of multilayers with total film thickness of ~ 350 Å and both surface and interface roughness less than 10 Å. Grazing incident X-ray diffraction pattern affirmed the very fine nano-sized crystallites embedded in majority amorphous matrix. Atomic force microscopy micrograph shows dense microstructure with 7 Å surface roughness of a film. Vibrating sample magnetometer study revealed the in-plane magnetic anisotropy in all investigated samples. In-plane coercivity is very low and normalized remanence is ~ 1. Out-of-plane coercivity is more than one order higher than that of in-plane and negligible remanence due to in-plane anisotropy. Longitudinal magneto-optical Kerr effect study shows in-plane uniaxial magnetic anisotropy. This magnetic multilayer system with uniaxial in-plane magnetic anisotropy is useful for magnetic device applications.