In order to establish the methodology for the preparation of the magnetic recording medium whose properties graded along the head field distribution, an intentional gradient control of coercivity, Hc, in electroless-deposited CoNiP thin films was attempted. Microstructure and Hc of the films changed significantly with the rotational speed of the substrate during deposition. Based upon these results, the gradient control of Hc was achieved by employing a programmed variation of the rotational speed of the substrate during the deposition. It was confirmed that not only "single-gradient" but also "dual-gradient" control of Hc in the direction of film thickness can be realized. This method is expected to be a useful technique for preparing a recording medium with magnetic propterties most suitable for recording system parameters such as head properties.
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