Abstracts---The magnetic properties, intergranular interactions, and recording noise of longitudinal CoCrTa/Cr thin film media have been investigated as a function of substrate temperature. It was found that the in-plane remanent coercivity was increased from 580 Oe for deposition at 25 QC to 1480 Oe for deposition at 220 QC. It was also found that preheating substrates to 270 QC reduced the medium noise power as much as 9.5 dB. Measurement of SM curves indicated that the dominant magnetic interactions in CoCrTa/Cr films was shifted from strong positive interactions, possibly intergranular exchange, to weaker negative magnetostatic interactions as the deposition temperature was increased. This reduction of magnetic coupling is believed to cause the decrease in the recording noise. In addition, the relation between recording noise and remanent coercivity squareness has been derived and their relationship was discussed on the basis of experimental results.

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Abstract---The magnetization reversal mechanisms in RF sputtered CoCr films with and without Cr underlayers have been investigated by measuring the angular dependence of the coercivity and hysteresis loss. Peak coercivity angles were observed to shift downward as the CoCr film thickness was increased for no Cr underlayers, and the shift direction was reversed with a thick Cr underlayer. Moreover, it was found that the Cr underlayers changed the magnetization reversal mechanism from domain wall motion to incoherent curling rotation in the thin CoCr films while the Cr underlayers had little influence on the switching modes in thick CoCr films.

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A bsrroet-The effects of grain morphology on the magnetic properties and transition noise, and their correlation with magnetic interactions of longitudinal CoCrTaICr thin film media have been studied. An increase of the Cr deposition temperature increases the Cr grain size resulting in a slight increase in the in-plane coercivity, but neither a reduction In magnetic coupling nor an improvement In signal to noise ratio was observed. However, an Increase of the CoCrTa deposition temperature was found to Increase the in-plane coercivity and reduce the transition noise significantly.