EFFECT OF SUBSTRATE ROUGHNESS ON MICROSTRUCTURE, UNIAXIAL ANISOTROPY, AND COERCIVITY OF CO/PT MULTILAYER THIN-FILMS

We studied the microstructure and magnetic properties of Co/Pt multilayer thin films sputtered onto glass and Si substrates with different surface roughness caused by different methods of substrate preparation. The microstructure determined by high-resolution electron microscopy and x-ray scattering could be correlated to the observed magnetic properties. Better (111) texture and smoother layer structures produced on smoother glass substrate surfaces produced higher uniaxial anisotropy. Coercivity, on the other hand, was enhanced by either pinning of the domain walls caused by substrate surface roughness or stronger columnar structure. Although Si substrates exhibited slightly different roughness under the same preparation conditions, the dependence of magnetic properties on the substrate surface was consistent with the trends using glass substrates.