Interfacial layer formation during high-temperature deposition of Sm-Co magnetic thin films on Si (100) substrates

The interfacial layer that has formed during the deposition of similar to 240-nm thick Sm-Co films on the bare Si (100) substrate was investigated at different deposition temperatures, T-d,T-Sm-Co: 400, 450 and 500 degrees C with respect to structural and magnetic properties of Sm-Co films. X-ray diffraction analysis showed the crystallization of both Sm2Co17(R) and SmCo5(H) magnetic phases. Rutherford back scattering studies demonstrated that the surface-diffusion reactions between the Sm-Co layer and Si-surface not only accompanied by the quasi-layered growth of CoSi2-phase; but also led to the formation of SmCoSi2-phase. Cross-sectional transmission electron microscopy analysis revealed uneven boundary with deeply grown CoSi2-layer and Moire fringes at limited regions of Co/Si interface. Magnetic measurements showed a square hysteresis loop with maximum values of coercivity (11.6 kOe) and remanence ratio (0.99) for the films grown at 500 degrees C. Magnetic force microscopy images depicted patch-like domains with increasing phase contrast against T-d,T-Sm-Co. In addition, the changes that has occurred in the magnetization reversal processes accompanied by coercivity enhancement due to higher T-d,T-Sm-Co is discussed in the context of domain morphology and first-order reversal curves.
Magnetic materials, Sm-Co films, Sputtering, Interdiffusion