North-Holland Surface properties and stray fields of rf-sputtered Co-Cr films

The influence of surface properties on the recording performance of thin films is at best illustrated in the perpendicular recording mode. The roughness and the oxidated/segregated top layer will redistribute the magnetic charges at the surface. The stray field which is so important in the reading process will deteriorate. Attention will be focussed on the relation between the stray field and magnetization (J.J. Miyata et al., IRE Trans. Elect. Comp. (19.59) 159) as a function of the above mentioned properties. Using experimental data the reduction of the maximum readable information density is calculated. The data used in this paper are obtained from rf The measured composition profiles were trans-sputtered Co-G films having a perpendicular anisot- formed to Magnetic Charge Density Distribution ropy 121. (MCDD) functions by assuming: The chemical composition of these films was deter-mined by XPS and Auger depth profiling. The oxide segregation scales of our Co-Cr films show a triplex character. At the surface only Co0 could be observed while the inner oxide scale mainly consisted of Cr,O,. The difference of the metal’s diffusion coefficients in the oxidized scale and the difference of the affinity fo