Comprehensive Theoretical and Experimental Analysis of Spin Waves in Magnetic Thin Film

Magnetic spin waves (SWs) have been induced and detected in a Ni₈₀Fe₂₀ thin film by two identical copper coplanar waveguides (CPWs). The dc fields up to 25 kA/m have been applied parallel to the CPWs, and magnetostatic surface SWs have been generated by applying voltages through the first CPW (source). The second CPW (pickup), 12 μm apart from the source, has been used to detect the ensuing SWs. Two independent setup and methods have been applied. Time domain SW measurements were performed by the application of voltage steps and the ensuing SW signal has been measured using a 16 GHz oscilloscope. Frequency domain SW spectroscopy was performed using a two-port vector network analyzer measurement in a frequency range from 10 MHz to 10 GHz. In addition, micromagnetic simulations were performed under the harmonic regime by assuming the induced SWs as perturbations of the saturated ground state excited by a small RF field. The numerically computed dispersion relation closely follows the Damon-Eshbach curve and is in good agreement with the experimental data.