Optimization of Co-Pt and Co-Cr-Pt-Ta thin films for use in magnetic data storage devices

Abstract

Co-Pt and Co-Cr-Pt-Ta thin films were deposited via magnetron deposition. The co-Pt films were deposited without heat or an underlayer. By proper optimization of sputtering conditions, it was found that 55 nm Co-Pt films with coercivities above 2300 Oe and saturation magnetizations of 760 emu cm -3 could be produced. Slower deposition rates, higher argon and base pressures produced the highest coercivity and lowest M s films. These results indicate the potential importance of grain boundary oxidation effects in determining the magnetic properties of these films. Results from atomic force microscopy and X-ray diffraction analysis of these films are also discussed. The influence of Pt content on the magnetic and recording properties of Co-Cr-Pt-Ta alloys was also studied. The platinum content was varied from 0 to 13 at.%. In general, the addition of platinum was found to decrease media saturation magnetization, coercive squareness and signal-to-noise ratio. Additions of a few atomic per cent platinum dramatically increased the coercivity of the alloy.