Positive correlation between coercivity and ferromagnetic resonance extrinsic linewidth in FeCoV/SiO_2 films

摘要

Dynamic magnetic properties of Fe_(49)Co_(49)V_2 thin films grown on Si/SiO_2 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 ℃ to about 400-500 ℃ and then on further increase of the growth temperature to increase in magnitude. Samples grown at about 400-450 ℃ 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 ℃. 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.