Investigation of structural and magnetic properties of cobalt chromium tantalum/cobalt(3) oxygen(4)/platinum perpendicular magnetic thin film media and MFM study of ultra-high density magnetic bit patterns

Investigation of the relationships between materials processing, crystalline structure, and magnetic properties of perpendicular CoCrTa magnetic thin film media has been investigated in this thesis.; A new tri-layer CoCrTa/Co{dollar}sb3{dollar}O{dollar}sb4{dollar}/Pt thin film has been developed to improve the structure and magnetic properties of perpendicular CoCrTa films. By individually manipulating the thickness of each layer to control the nucleation and growth of the films, CoCrTa films with strong crystalline orientation texture, fine crystalline grain feature, desirable perpendicular magnetic properties (including small in-plane squareness S{dollar}sb{lcub}//{rcub},{dollar} large R (the ratio between Hc{dollar}sbbot{dollar} and Hc{dollar}sb{lcub}//{rcub}),{dollar} relatively high perpendicular coercivity Hc{dollar}sbbot,{dollar} and sharp perpendicular nucleation field Hn{dollar}sbbotrbrack{dollar} can be achieved by room temperature RF sputtering deposition. The effects of deposition parameters on the structure and magnetic properties of CoCrTa films are also investigated. Specifically, changing the atom mobility during the sputtering of Pt buffer layer by changing the sputtering gas pressure and the substrate bias voltage influences its crystalline texture, which in turn affects the structure and magnetic properties of CoCrTa films.; The evolution of surface morphologies of the tri-layer CoCrTa/Co{dollar}sb3{dollar}O{dollar}sb4{dollar}/Pt films with CoCrTa thickness has been studied using atomic force microscope (AFM). The height-height correlation functions obtained from the AFM images of the CoCrTa films indicate a scaling behavior of the surface morphologies. For these films, the local surface morphology parameter {dollar}alpha{dollar} reaches a value of 0.9 when the film thickness exceeds 2,000 A because of the equilibrium of two competing processes. The global surface interface width increases with film thickness. The scaling parameter {dollar}beta{dollar} obtained from the height-height correlation function is 0.26.; In the thesis, magnetic force microscope (MFM) has also been used to study bit patterns recorded on longitudinal and perpendicular media at different recording densities. Media relaxation in the forms of local domain reversal and the formation of large domains within high density tracks is the major reason that limit bit detectability at ultra-high densities for perpendicular media.