Magnetic properties and recording performance of multilayer films of CoCrTa, CoCrPtTa, and CoCrPtTa with CoCrPtB

Magnetic media composed of thin Cr layers between layers of CoCrTa, CoCrPtTa, or CoCrPtTa with CoCrPtB were fabricated and tested. The effects of the Cr interlayer thickness, and the ratio of top and bottom layer thickness on magnetic recording performance-were evaluated for the different materials. Results show that signal-to-noise performance improves and other recording properties, such as pulse width, generally degrade. The cases of multilayers composed of a top layer of CoCrPtTa and a bottom layer of CoCrPtTa or CoCrPtB show the unusual behavior that not only can noise characteristics be improved compared to single layer films, but optimization of the film geometry can produce pulse width and overwrite without significant degradation. This behavior is attributed to coercivity gradients and independent switching behavior of the top and bottom films