| This dissertation describes a comprehensive investigation directed at optimizing and understanding the micro-structural and magnetic properties of barium ferrite perpendicular media.; The use of a Pt underlayer and the use of a seedlayer, such as sputtered Y2O3 or sputtered amorphous barium ferrite, were found to be very effective in promoting the texture growth of (00l) c-axis orientation. It was also found that perpendicular c-axis orientation was greatly improved for films with Pt interlayers. A mechanism, which explains the effect of the Pt interlayers in enhancing the perpendicular anisotropy for barium ferrite, is also proposed.; Greatly reduced grain sizes and strong (00l) c-axis texture were obtained by increasing the relative barium content and optimizing the processing parameters for perpendicular barium ferrite thin films. Small grains of about 300 Å were obtained with 10 wt% barium rich barium ferrite thin films. Perpendicular c-axis orientation for 10 wt% barium rich barium ferrite was achieved on the thermally oxidized Si substrate, SiN substrate, Si substrate, BaO underlayer and Pt underlayer respectively. To have a better understanding of the stoichiometry effects on the magnetic and structural properties, barium ferrite thin films with compositions of BaO•n(Fe 2O3) with n varying gradually from 1.5 to 8 were systematically studied. It is believed that the decrease of the grain size for barium rich films can be related to the existence of nonmagnetic phase BaFe2O 4, which will inhibit the motion of the grain boundary, thereby decreasing their rate of growth and their ultimate size for barium ferrite grains. The effects of a Pt underlayer, different seedlayers, a Pt interlayer on the textured growth for the stoichiometric and non-stoichiometric strontium ferrite films were also studied.; To use barium ferrite or strontium ferrite thin film as high-density perpendicular recording media, a suitable soft magnetic underlayer needs to be developed. Sendust was demonstrated to be a suitable soft underlayer for barium ferrite and strontium ferrite. Ba(Sr)M/Pt/Ba(Sr)M/FeAlSi multilayer films were found to have the best overall properties. The use of a Pt intermediate layer and the use of an amorphous barium/strontium ferrite buffer layer are very effective in improving the perpendicular c-axis texture for the barium/strontium ferrite hard layer, while retaining the soft magnetic properties of the sendust layer. |
