Effects of CrAl underlayer and intermediate layer on the properties of CoCrPtTa thin film media

This study investigates the effects of CrAl underlayer and intermediate layer on the magnetic properties, crystallographic texture, and thermal stability of CoCrPtTa thin film media. Enhancement of coercivity and thermal stability factor of CoCrPtTa/CrAl _x thin film media were observed when the Al concentration in the CrAl underlayer was varied from 0 to 14 at.%. We also observed an improvement in the in-plane crystallographic texture and a reduction in the magnetic switching volume and intergrain interaction. Results from the interdiffusion study using Auger depth profiling analysis, and ΔM measurement showed that the decrease of switching volume and intergrain interaction may be attributed to Al diffusion and/or Al-enhanced Cr diffusion into the grain boundary of the magnetic layer. Compared to CoCrPtTa/Cr media, we found that high coercivity, good in-plane crystallographic texture, and magnetic isolation for CoCrPtTa/CrAl media could be achieved at lower substrate temperature. This study has also shown that a CrAl intermediate layer could be used to further enhance the magnetic, crystallographic texture, and thermal stability properties of the CoCrPtTa thin film media.