Thin-film recording media on flexible substrates for tape applications

Co-based alloys were investigated as candidates for sputtered thin-film magnetic tape media. Magnetic media on polymeric substrates having acceptable magnetic properties were obtained by applying NiAl/CrMn underlayers prior to CoCrPt deposition with a nonmagnetic CoCrTa intermediate layer. Typical sputtered tape media deposited on traditional polymeric substrates at room temperature revealed sideband modulation noise and large intergranular exchange coupling. A substantial improvement in surface roughness by utilizing smooth polymeric substrates eliminated this modulation noise and accounted for the signal dependent broad-band noise power. This suggests that transition noise is a dominant component of medium noise in sputtered tape media. Additionally, substrate bias is shown to be effective in producing grain decoupling that is necessary for good signal-to-noise ratio.