Publication

Abstract : Magnetic thin films with a layer sequence of Si|CoSi2|Sm-Co were grown by direct sputter deposition at elevated temperatures, through interfacial diffusion between Si (1 0 0) substrate and the overlying Sm-Co layer. HR-TEM analysis revealed the occurrence of CoSi2-interfacial layer close to the Si-substrate surface, with controllable thicknesses of ~20 and 35 nm at deposition temperatures: 450 and 500 °C, respectively. XRD studies confirmed the crystallization of Sm2Co17 and SmCo5 magnetic phases accompanied by the other phases such as CoSi2 and SmCoSi2 due to the intermixing of Co and Si -atoms at higher deposition temperatures. The measured coercivity values are found to be increased from 8.7 to 11.6 kOe at higher CoSi2-layer thickness. The angular-dependent hysteresis measurements demonstrated a distinct isotropic and uniaxial magnetic anisotropy characteristics for the Sm-Co films consisting of 35 and 20-nm thick CoSi2 interfacial layers, respectively and the associated magnetization reversal mechanisms are discussed using the Stoner-Wohlfarth model. The temperature coefficients of remanence (α) and coercivity (β) were determined from the temperature-dependent hysteresis curves. The Sm-Co films consisting of 35-nm thick CoSi2-layer exhibited a better thermal stability with ‘α’ and ‘β’ values of 0.35 ± 0.05%/°C and −0.13 ± 0.02%/°C, respectively. The results of present study provide splendid opportunities for exploiting the potential of CoSi2 as an under layer, for growing the Sm-Co films towards high-temperature applications.