Study of nanocrystalline soft magnetic material of an Fe-Si-Al-n film with high saturation magnetization and low SUL noise

摘要

To develop nanocrystalline soft magnetic underlayer (SUL) material with high saturation magnetization and low SUL noise, we studied the properties of an Fe-Si-Al-N film. To obtain SUL with high stray-field stability, the Fe-Si-Al-N film is applied to antiferro/ferromagnetic (AFM/FM) multilayer films. As the results, the following points are clarified: 1) As the composition of FeSiAlN film, with increasing nitrogen flow ratio, Fe is replace with N on constant Al + Si concentration line. 2) With increasing nitrogen content, soft magnetic properties of FeSiAIN film are increased due to nanocrystalline effect. 3) As the grain size of FeSiAIN film is decreased, the SUL noise of FeSiAIN film is reduced. Since subsequent high temperature annealing process is not necessary, this process is promising to be applied for moderate temperature process. 4) In the AFM/FM stacked SUL film, the unidirectional exchange energy J{sub}k is decreased with the total magnetization of the film.