TiN and TiC Intermediate Layers for FePt-C-Based Magnetic Recording Media

Conductive TiN and TiC intermediate layers were used to promote epitaxial growth of (001)-textured FePt in place of the traditional nonconductive MgO intermediate layer. The film structure was given by glass substrate/Cr $_{90}$ Ru $_{10}$ /(TiC or TiN)/FePt-C. The films were fabricated under constant deposition temperature of 350 $^{\circ}$ C for all three layers. Both TiN and TiC were capable of inducing (001)-textured FePt with square magnetic hysteresis loops and out-of-plane coercivity of up to 4 kOe. Further increase in deposition temperature of FePt recording layer up to 500 $^{\circ}$ C resulted in monotonic increases in coercivity of up to 9 kOe while still maintaining strong perpendicular anisotropy, large magnetic squareness, and a small in-plane component. Subsequent doping of up to 40 vol. % C in FePt led to increases of coercivity beyond 14 kOe with reduction in intergranular lateral exchange coupling.