Effects of Microstructure and Crystallography on the Magnetic Properties of CoCrPt/Cr Thin Films

Abstract

ABSTRACTThe effects of grain morphology and crystallography on the magnetic properties of CoCrPt/Cr thin films were investigated as a function of sputtering parameters of CoCrPt thin films. Cross sectional TEM exhibited strong separation of Co grains with increasing argon sputtering pressure, resulting in reduced exchange coupling and increased coercivity. Most Co grains sputtered at high pressure were separated by 10 to 20 Å thick boundaries, possibly due to the enhanced scattering of argon ions by sputtering particles and thus the observed higher content of Pt in the deposited films. The application of substrate bias greatly decreased the Co grain separation and the nonmagnetic grain boundary disappeared by -200 V bias sputtering, resulting in increased exchange coupling. The bias sputtered CoCrPt thin films decreased their grain size and increased epitaxial growth on Cr layer and also (1010) texture. The magnetic field required to saturate the film increased significantly with increasing substrate bias, possibly due to the induced residual stress in the bias sputtered films.