Fabrication And Magnetic Properties Of CoPt Films With Perpendicular Anisotropy

With the increasing demand for greater capacity and higher density of the recordingmedia, the traditional longitudinal magnetic recording technology has met its physical limit.The perpendicular magnetic recording media has been proposed in magnetic recordingtechnology to overcome the problem of superparamagnetic limits. L10-CoPt thin film mediawith high magnetocrystalline anisotropy energy has attracted considerable interests in thenear future. The face cubic tetragonal (fct) ordered alloys exhibit great potential forhigh-density magnetic media because of their capability to achieve extremely small grainsizes to keep thermal stability, high coercivity and magnetocrystalline anisotropy energy(4.9×107erg/cm3for CoPt).In this thesis, CoPt films were fabricated by DC magnetron sputtering system on aP-type thermally oxidized substrate of Si/SiO2. First of all, we studied the effect of heatingof the substrate and different thicknesses on the magnetic properties of Co78Pt22film，magnetic properties of Co-Pt alloy films with different atomic ratios and Taseedlayer.Moreover, the effects of sputtering parameters （such as sputtering power、thepressure of Ar）on CoPt film magnetic properties were investigated. The fabricationparameters have been optimized to improve the magnetic properties of CoPt/Ta.Last but not least, some modern analytical test methods of XRD, VSM, XPS wereapplied to research the microstructures and magnetic properties of CoPt/Ta film and CoPtfilm. In this study, we reported that the magnetic properties of CoPt thin films capped withTa layer were better than those of CoPt single-layer. In the annealing process,Ta preventedCoPt films from corrosion and oxidation because Ta can react with oxygen to formprotective coating layer. The perpendicular magnetic properties were improved greatly.Besides, thermal diffusion of Ta atoms into the CoPt layer signifcantly decreased theexchange interaction among the magnetic grains. Hence， the enhancement of the(001)-preferred growth in the film was obtained.