Noise Properties of a Perpendicular/Longitudinal Composite Medium Prepared by Sputtering.

The read-write characteristics of a perpendicular/longitudinal composite medium prepared by sputtering were investigated. The composite medium exhibited a higher voltage than a perpendicular single-layered medium, although the noise of these media was almost the same. The noise of the composite medium increased slightly with the recording density, suggesting that it was affected by the longitudinal underlayer. However, the noise reduction effect of the composite medium was observed by comparing with the simple superposition of the noise of each single layered medium. As a result, it was found that the perpendicular/longitudinal composite medium exhibited a higher S/N value than the perpendicular single-layered medium.