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

摘要

The soft under layer (SUL) is used to improve write head filed strength, field gradient and read-back signal in perpendicular magnetic media [1]. But the detrimental effect is produced by SUL noise, which is generated by domain walls in ferromagnetic layer of SUL. There are various methods to eliminate domain walls, i.e., make pseudo single domain such as repeated multilayer, exchange bias and synthetic coupling types [2-4]. In this study, we fabricated four type SUL structures to compare with the magnetic properties, domain structure and noise level of various SUL structures before and after annealing procedures.