Perpendicular/longitudinal composite media having a Ni(-Cr) alloy as a longitudinal magnetic underlayer were prepared by dc-magnetron sputtering. All the diffraction peaks observed in XRD experiments were Ni(111) and Co(002), indicating that composite media without an intermediate layer were successfully prepared. To obtain a higher S/N value, it was revealed that it is effective to decrease the thickness and saturation magnetization of the Ni alloy longitudinal magnetic layer. However, using a Ti underlayer caused higher medium noise.
