DESIGN AND CRYSTALLOGRAPHY OF MULTILAYERED MEDIA

In this paper several different schemes for multilayered longitudinal magnetic recording media are presented and discussed. We will focus th e discussion on those schemes on which we have worked over the past se veral years, emphasizing the role of new underlayers, seed layers, int ermediate layers and interlayers. In each case we discuss the role tha t each of the layers plays in determining the important magnetic prope rties and recording performance of the Co based hcp thin film media. I ncluded in the paper is a review of the role of new underlayers (NiAl and MgO), seed layers (MgO), intermediate layers (Cr, Co alloys) and i nterlayers (Cr, Al, Cu and Ag). Throughout we discuss the role of epit axy between the various layers and demonstrate that the resulting micr ostructure and crystallographic texture of the films depends strongly on such epitaxy. These characteristics, in turn, control the resulting magnetic properties of the Co based films such as in plane coercivity H-c and squareness ratio, S.