Method for making horizontal magnetic recording media having grains of chemically-ordered FePt or CoPt

A method for making a magnetic recording disk for horizontal magnetic recording comprising:

• providing a disk substrate;
• sputter depositing on the substrate a seed layer of nonmagnetic material selected from the group consisting of Pt, Pd, Cr, CrV, SiN, NiAl(B.sub.2) alloy, FeAl(B.sub.2) alloy, and CrMn alloy;
• sputter etching the seed layer down to a thickness in the range of approximately 1-10 nm to form a seed layer structure of discontinuous columns of nonmagnetic seed layer material on the substrate;
• and
• while maintaining the substrate at a temperature in the range of approximately 250-700.degree. C., sputter depositing directly over the etched seed layer structure a film comprising generally equiatomic amounts of a first element of Pt or Pd and a second element of Co or Fe, and a third element selected from the group consisting of Cr, Ag, Cu, Ta, and B, the film having discrete magnetic grains of a generally chemically-ordered alloy of said first element and said second element with said third element being located substantially at the grain boundaries to enhance the magnetic decoupling between the grains, said chemically-ordered alloy in the magnetic grains having a substantially tetragonal crystalline structure with the main component of the C-axis and thereby the magnetization being in the plane of the film, the tetragonal crystalline structure in the grains being present after sputter deposition and without subsequent annealing.