High anisotropy L10 thin films for longitudinal recording

Bulk L1₀ phase materials, such as CoPt and FePt, are known for their high magnetocrystalline anisotropy and magnetic moment, properties that are also desirable for high density magnetic recording media. This work reports the preparation, microstructural characterization, magnetic properties, and magnetic recording performance of L1₀ phase thin (25 Å to 200 Å) films. The samples are prepared by sputter deposition and ex-situ anneal. The microstructural characterization is by transmission electron microscopy and X-ray diffraction. High magnetocrystalline anisotropy is apparently maintained for even the thinnest films, where coercivity, H _c, >10,000 Oe is observed for a 25 Å sample. The H _c of films prepared for magnetic recording measurements is considerably less to ensure that test patterns could be written. Samples for recording measurements were obtained by a reduction in anneal temperature or the codeposition of an oxide with the L1₀ phase material to limit grain growth during anneal