Effects of Cr-N-ZrO2 seed layer formed on glass substrates for longitudinal recording media

Effects of Cr-N-ZrO2 seed layer deposited on glass substrates before the de position of C/Co-Cr-Pt/Cr-Ti layers for longitudinal recording media have b een investigated. The product of upsilon and I-s, the activation volume and the saturation magnetization per unit volume, media noise N-d and S-0/N-d, which is the half value of peak-to-peak output voltage of an isolated puls e over N-d at 11.8 kFC/mm, are evaluated. We find that upsilon I-s is decre ased by adding N and ZrO2 to Cr seed layer, N-d is reduced as upsilon I-s d ecreases by adding nitrogen to the Cr seed layer. This is mainly due to the decreased grain sizes of both Cr-Ti underlayer and Co-Cr-Pt magnetic layer . The N-d is further reduced by the addition of ZrO2 to the Cr-N seed layer . Highest S-0/N-d is achieved for the media with Cr-N-ZrO2 seed layer. On t he other hand, the media with Cr-ZrO2 seed layer deposited without nitrogen show the higher N-d. Therefore the decrease of the grain size by addition of nitrogen into Ar is essential to reduce N-d, and the ZrO2 addition to th e Cr-N seed layer seems to enhance the effect of grain site reduction by ni trogen addition. (C) 1999 Elsevier Science B.V. All rights reserved.