Recording Characteristics of Co-Cr/Ni-Fe Double-Layered Tape

The magnetic and recording characteristics of a Co-Cr/Ni-Fe double-layered tape medium for perpendicular magnetic recording were investigated. The Co-Cr/Ni-Fe tape medium was prepared on a 10 mm-thick polyimide sheet using a Facing Targets Sputtering (FTS) system. The requirements imposed on Co-Cr/Ni-Fe tape media for use in conventional VTR systems, such as flexibility and a high mi of the Ni-Fe layer, were examined. In order to improve the mi of the Co-Cr/Ni-Fe tape medium, which is decreased by magnetic interaction between the Ni-Fe layer and the Co-Cr recording layer, a 0.03 mm thick Co67Cr33 intermediate layer with a small Ms of 51 emu/cc was prepared. Recording and reproducing experiments using a helical-scan VTR machine were carried out for the Co-Cr/Ni-Fe tape. A reproduced output of 115 nVo-p/(mm-T-m/s) at a low linear bit density and a C/N ratio of 51.4 dB at 61 kFRPI (R.B.W.=10 kHz) were obtained by using a Transverse Returning Flux (TRF) head with a 0.2 mm-thick main pole.