Positive correlation between coercivity and ferromagnetic resonance extrinsic linewidth in FeCoV/SiO2 films

Dynamic magnetic properties of Fe49Co49V2 thin films grown on Si/SiO2 substrates have been studied by using ferromagnetic resonance technique. The effective Lande g-factor, extrinsic linewidth, and Gilbert relaxation rate are all found to decrease in magnitude with increasing sample growth temperature from 20 degrees C to about 400-500 degrees C and then on further increase of the growth temperature to increase in magnitude. Samples grown at about 400-450 degrees C display the smallest coercivity, while the smallest value of the Gilbert relaxation rate of about 0.1 GHz is obtained for samples grown at 450-500 degrees C. An almost linear relation between extrinsic linewidth and coercivity is observed, which suggests a positive correlation between magnetic inhomogeneity, coercivity, and extrinsic linewidth. The Gilbert relaxation is found to decrease with increasing lattice constant, which is ascribed to the degree of structural order in the films. (C) 2014 AIP Publishing LLC.