Temperature and seed layer effects on the magnetics of sputtered glass-ceramic disks

Abstract

Glass-ceramic substrates show excellent shock resistance and low glide performance. To achieve good magnetics, two types of seed layers, A and B, and no seed layer were deposited on glass-ceramic substrates with following Cr and CoCrPtTa layers. The effects of the seed layers on the substrate temperature, the subsequent Cr and CoCrPtTa crystallographic orientations, anisotropy K u , media noise and the signal-to-noise ratio (SNR) were measured. The seed layer reduces the emissivity of the glass and increases the substrate temperature by more than 100°C during the Co layer deposition. Significant differences in media noise performance were observed among the three seed layer materials and processes. The textures of the Cr underlayer and the Co alloy depend on the surface of the seed layer. Samples with Ni 3P seed layers have a structure with Co(11 2 0)/Cr(200) on Ni 3P and show SNR values 2–6 dB higher than those with Cr seed layers. However, the Δ M curves show that samples with Ni 3P seed layers have higher Δ M. The Δ M value may not be a necessary condition for determining the mechanism of media noise.