Gyromagnetic damping and the role of spin-wave generation in pulsed inductive microwave magnetometry

Abstract

The dependence of the magnetodynamic response of thin permalloy films was measured with a pulsed inductive microwave magnetometer as a function of varying width of the coplanar waveguide center conductor (220 to 990 υm), frequency (0.6 to 2 GHz) and film thickness (25 to 93 nm) to ascertain the role of magnetostatic spin-wave generation in the low-frequency enhancement of the measured decay rate. A component of the decay rate depends on δ_w, the ratio of film thickness to center conductor width as theoretically predicted. However, there is an anomalous contribution to the frequency dependence of the decay rate exists that cannot be attributed to the generation of spin-waves.