Influence of annealing on boron diffusion from obliquely sputtered Co60Fe20B20 thin films

We report controlled effect of Boron diffusion on annealing of Co60Fe20B20 (CoFeB) thin films grown on SiO2/Si(100) substrates using pulsed dc magnetron sputtering. X-ray diffraction studies indicated that the crystallization of CoFeB is achieved above 100°C via the formation of bcc CoFe with (110) preferred orientation. Saturation magnetization (µOMs) of the as-deposited film is found to be 1000 kA/m, which enhances upon annealing such that a value of µOMs of 1375 kA/m is observed in the sample annealed at 400°C while the coercivity decreases from 12 mT to 2 mT. A lowest value of 0.005±0.002 of the damping constant is evidenced for the sample annealed at 400°C. The tunability of the damping constant via the Boron out-diffusion from CFB achieved by controlling the annealing temperature is certainly important for spintronics device applications.