Magnetic Properties and Microstructure of FePt(MoC, C) Granular Films

The FePt-Mo
₄₀
C
₆₀
(x vol%)/MoC/CrRu (x = 0, 7, 10, 15, 20, and 25) films were deposited on glass substrates by magnetron sputtering. The Mo
₄₀
C
₆₀
target was used as material of intermediate layer and segregant and formed the MoC and C two phases after deposition. The MoC(200) intermediate layer was epitaxially grown on the (200) textured CrRu seed layer at 425 °C. The FePt-MoC film was cosputtered on (200) textured MoC at 425 °C and showed the strong (001) texture. The out-of-plane coercivity of FePt-MoC(7 vol%) film was changed to 7.8 kOe compared with that of a 10-nm thick FePt film. When MoC was added more than 10 vol%, the ordering degree and perpendicular magnetic anisotropy were degraded. The out-of-plane coercivity decreased and in-plane loops open up. For microstructure, the FePt grains were separated by (MoC and C) and formed the granular structure. From cross-sectional images, the FePt-MoC(7 vol%) film was island like and changed to continuous layer in a FePt-MoC(15 and 25 vol%) film.