Isolated pulses in particulate and thin film media

Measurements were made of the half pulse widths (PW/sub 50/s) of advanced small rigid disks coated with high-coercivity thin metallic films and with oriented particulate dispersions of Co-gamma and Ba-ferrite, using various narrow-gap heads of thin film, MnZn-ferrite, and MIG. One object of the study was to determine how close the experimental values of PW/sub 50/ for these different media/head combinations correlate with the predictions of simple theoretical models based on arctan magnetization transitions. A second object of the study was to determine whether the observed PW/sub 50/s correlate with the high density response of these various media/head combinations. A good correlation was found between theory and experiment, in spite of the simple theoretical model used. The PW/sub 50/s of the Ba-ferrite media are between those of the thin-film media and the Co-gamma media, but the recording performance of Ba-ferrite is much closer to that of thin film. This indicates that recording demagnetization losses are also important and that they extract a different toll depending on the type of media and their remanence loop characteristics.<
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