Noise origin of Co–Cr–Ta films on ultra-flat glass-ceramic and Si substrates for longitudinal recording disks

Abstract Co 85 Cr 13 Ta 2 /Cr bilayered films for longitudinal recording disks were deposited by plasma-enhanced facing targets sputtering apparatus on 2.5 in and ultra-flat disk substrates of glass-ceramic and single-crystal silicon. Their noise and read/write characteristics were almost comparable with those of the high-performance disks using Co–Cr–Pt films, with coercivity H c of 2.4 kOe, as a reference disk, even though the Co–Cr–Ta films exhibited macroscopic H c of only 800 Oe. Co 85 Cr 13 Ta 2 films are known as low-noise media. This study addresses the problem of how to obtain low-noise media, using excellent sputtering apparatus and disk substrate materials, to allow practical applications in ultra-high-density recording systems, including 1 in microdrives for mobile applications.