Fig. 4: Spin wave tomography analysis for bi-reflection of spin waves.
a Spin wave tomography spectrum for the incident mode as a function of the wavenumber and frequency. White dashed lines indicate the calculated dispersion relation of spin waves (SW), longitudinal (LA), and transverse (TA) elastic waves. The velocity of the longitudinal and transverse elastic waves are 6.5 km s−1 and 3.5 km s−1, respectively. b Same as (a) but along k1 vector. c Same as (a) but along k2. d Temporal evolution of a cross-sectional view of the magneto-optical images cut along kin. e Same in (d) but the envelope data obtained by Hilbert transform are plotted. The slope of the red dashed line in the figure indicates the phase (group) velocity in d (e). In (e), the red dashed line in (d) is drawn with a white dashed line for a comparison. f Shows the calculated dispersion relation, and (g) shows the calculated amplitude of the spin-wave component and the elastic-wave component near the crossing between the longitudinal elastic waves and spin waves. Purple solid curves in (f, g) between black dashed vertical lines highlight the region having the group velocity obtained from (e). h Reflection angles plotted as a function of the incident angle. The blue (red) filled circles indicate the reflection angles of the k1 (k2) mode. Solid curves show the result of the calculation. The error bars are evaluated from standard deviation of two-dimensional gaussian fitting parameters. i Reflectivity of each modes as a function of the incident angle. The blue (red) filled circles indicate the reflectivity of k1 (k2) modes. Black dashed curves are the reflectivity of the pure elastic waves. The solid blue (red) curves shows the result of the model calculation. The error bars are evaluated from standard deviation of two-dimensional gaussian fitting parameters.
