Structural and ferromagnetic response of Fe₃Si thin films on Si(0 0 1) to sputter-deposition rate and post-deposition annealing

Fe3Si thin films were deposited on Si(001) by magnetron dc sputtering with varying deposition rates. As-deposited Fe3Si film from low deposition rate has a coercive field H-c of 5 Oe, saturation magnetization M-s of similar to 920 emu cm(-3) and remanent magnetization M-r similar to 0.9M(s) that are maintained upon post-deposition annealing (PDA) at 350 degrees C. In contrast, the magnetic properties of Fe3Si deposited from high rates degrade with PDA-H-c increases from 1 to 14Oe while M-s decreases from similar to 940 to 590 emu cm(-3). Structural investigations show that Fe3Si deposited with a low rate is polycrystalline while Fe3Si with a high rate is amorphous with significant differences observed at the Fe3Si/Si interfaces. The structural differences were attributed to the influence of the deposition rate on the grain nucleation and microstructural morphology in the as-deposited Fe3Si and the subsequent annealed films, which in turn determine the ferromagnetic response.