Thermal and Magnetic Field Effect of Soft Under Layer for Perpendicular Media

The soft under layer (SUL) is used to improve write head filed strength, field gradient and read-back signal in perpendicular magnetic media. In this study, four type SUL structures were fabricated. Samples were post-annealed and cooled to room temperature under magnetic field along radial direction. VSM, MFM and Guzik spin stand were used to analyze the magnetic properties, domain structure and noise level of the samples.