Read and write characteristics of Co-Ni-Zr-M/Cr thin films for longitudinal recording

The magnetic and crystallographic properties and read and write characteristics of sputtered C/Co-Ni-Zr/Cr and C/Co-Ni-Zr-M/Cr (M=V, Nb, Ta, Cr, Mo, W, Cu, Si, Al, Ru and Pt) thin films are investigated. The saturation magnetic flux density B_s of all C/Co-Ni-Zr-M/Cr films decreases as the amount of additive element increases. The coercivity of C/Co-Ni-Zr-Cr/Cr and C/Co-Ni-Zr-Pt/Cr is higher than that of C/Co-Ni-Zr/Cr films with comparable B_s . The larger the perpendicular anisotropy K_p and the smaller the anisotropy constant K_n, the lower the media noise N and the higher the S/N ratio. The reduction of K_n and N are strongly connected to grain separation and grain size reduction. The larger the B_s·tmag, the higher E_II and N and the lower D ₅₀ and the S/N ratio. All films except those with Si, Ru, and Pt additives have large K_p, a small K_n, and a high S/N ratio. In particular, C/Co-Ni-Zr-M/Cr (M=Cr, Mo, W, and Al) disks have a better S/N ratio and D₅₀ than C/Co-Ni-Zr/Cr disks