Preparation of highly stable TbFeCo thin films by plasma-free sputtering at high rate

TbFeCo films have been prepared at the deposition rate of 100 nm/min on plasma-free substrates by using the facing-targets type of sputtering method. These films showed a uniform and columnless microstructure composed of dense fine grains. The effect of annealing on the optical, magnetic, and magnetooptical properties was investigated in some unprotected TbFeCo films. In the 100-nm-thick TbFeCo/PMMA media, there was no considerable change in the reflectivity of the TbFeCo layer even after exposure to the ambient air for 28 months. The rectangular Kerr hysteresis loop of the media was kept well. In an accelerated aging test at a temperature of 50-70 degrees C and relative humidity of 60% on the 250-nm-thick TbFeCo/glass media, there was no significant decrease of perpendicular magnetic anisotropy energy for an aging time of 150 h. These results suggest that the stability of these media is strongly correlated with the microstructure of the TbFeCo films. The preparation of the columnless films with dense and uniform microstructure should improve the stability and corrosion resistance of the TbFeCo films.<
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