Read and write characteristics of Co-alloy/Cr thin films for longitudinal recording

Magnetic and corrosion properties and read and write characteristics of sputtered C/Co-Ni-M/Cr and C/Co-Cr-M/Cr (M=Pt, Ta and Zr) thin films are investigated. The addition of a small amount of Pt, Ta, and Zr to Co-alloy films improves both corrosion resistance and coercivity. Media noise has almost no correlation with coercivity but is proportional to the effective demagnetization energy. This is because the transition length of the medium can be narrow due to the small demagnetization energy at magnetization reversals. C/Co-Ni-Zr/Cr and C/Co-Cr-Ta/Cr disks, with large perpendicular anisotropy constant and small demagnetization energy, have an excellent S/N ratio and recording density