Thin film media with and without bicrystal cluster structure on glass ceramic substrates

The effect of bicrystal structure on media noise was studied experimentally. Disk samples with and without bicrystal structures have been produced on glass ceramic substrates using different Co/Cr epitaxial systems, (11(2) over bar 0)//(200) and (10(1) over bar 1)//(110). With similar magnetic properties and grain size, the former sample with the bicrystal structure has 5 dB better signal-to-noise ratio (SNR), even though the delta M curve suggests that the sample with bicrystal structure has stronger intergranular exchange coupling. The interface between NiP and Cr of the sample with bicrystals is rougher than that of the sample without bicrystals. It is suggested that the micro-roughness of the interface between NiP and Cr could affect the formation of Cr(200) texture.