Ferrite thin film disks using electroless-plated Ni-P substrates

Ferrite thin film disks using electroless-plated Ni-P substrates have been prepared. The practicability of attaining these disks at areal densities above 4.7 X l0⁴bits/mm²(28 K-FRPI X 1100 TPI) has been confirmed from the following view points: read/write and error characteristics, signal-to-noise ratio (SNR), and wear durabilities. Over -20 K-FRPI, noise level decreases were found. As a result, more than SNR 35 dB at 40-50 K-FRPI were attained. Practical feasibilities were also confirmed at 40-50 K-FRPI. In wear durability, 20 000 contact-start-stop operations were achieved.