Static and dynamic magnetic properties of bcc Fe49Co49V2 thin films on Si(100) substrates

Thin films of Fe49Co49V2 have been grown on Si(1 0 0) substrates by dc magnetron sputtering varying the substrate temperature in the range from room temperature (RT) to 600 degrees C. The static magnetic properties of the films were studied using a superconducting quantum interference device and magneto-optic Kerr effect magnetometry, while x-ray diffraction and reflectivity measurements have been used for the evaluation of the structural properties and thickness of the prepared samples. The easy axis coercivity decreases from 60 Oe for the sample grown at RT to 15 Oe for the one grown at 400 degrees C. We also studied the dynamic magnetic properties of the samples by using the high-frequency vector network analyser ferromagnetic resonance (FMR) technique. Results from FMR measurements show that the extrinsic linewidth decreases with increasing growth temperature up to 450 degrees C and then increases with further increase of growth temperature. The source of the extrinsic linewidth is two-magnon scattering by small, weak inhomogeneities. The intrinsic Gilbert damping (alpha) follows a similar trend to the extrinsic linewidth, with the lowest damping constant alpha approximate to 0.005 found at a growth temperature of 450 degrees C.