Effect of rapid thermal annealing on the structure, microstructure and magnetic properties of Fe thin films

This paper reports the structure, microstructure and magnetic properties of as-deposited and rapid thermal annealed Fe thin films Rapid thermal annealing was carried out at 550 degrees C for different time intervals such as 2, 5, 10, 20 and 30 min. The as-deposited and rapid thermal annealed films were found to exhibit A2 type bcc structure. However, microstructural studies indicated formation of Fe-Si phase for the annealed Fe films Surface roughness estimated from atomic force microscopy studies displayed an increase in surface roughness with increase in annealing time. Room temperature magnetization studies showed a predominant in-plane magnetic anisotropy for all the films In addition to this presence of strong out-of-plane anisotropy coupled with in-plane magnetization was clearly evidenced from the considerable increase in the out-of-plane coercivity with increase in annealing time. Magnetic force microscopy studies further confirmed the presence of out-of-plane magnetic anisotropy. Magnetic domain imaging studies showed long period band domain patterns with 180 degrees domain wall for the as-deposited film. The band domains were found to get branched with increase in annealing time. From the hysteresis loops and domain imaging studies it was clear that the magnetization reversal is dominated by domain wall motion.