The Effects of SiNx Underlayer’s Stress Status on Magnetic and Recording Properties of SiNx/TbFeCo/SiNx Trilayers
Dr. T. E. Shieh
This work studied the effects of stress statuses of SiNx underlayer on the magnetic and recording properties of SiNx/TbFeCo/SiNx trilayers. By adjusting the deposited parameters of SiNx underlayer, such as working pressure, Ar/N2 ratio, and thickness, the TbFeCo might exhibit strong perpendicular anisotropy when SiNx underlayer possessed large compressive stress. We also found that the compressive stress enhanced the coercivity squareness of TbFeCo. The observation of initial M-H curves revealed that the switching mechanism of TbFeCo strongly depended on the deposition conditions of SiNx underlayer. When the SiNx underlayers were subjected to a compressive stress, magnetization switching of TbFeCo films preferred the nucleation mechanism. The contribution of compressive stress to magnetization reversal was obvious when changing the working pressure of deposition. The experiment of recording properties indicated that the media noise could be effectively reduced when the SiNx underlayer possessed a strong compressive stress. The compressive stress status also enhanced the perpendicular unaxial anisotropy (Ku) of MO trilayer. Our experimental results indicated that the storage density of MO disk could reach about 10 Gbit/inch2.