Experimental Visualization of Dispersion Characteristics of Backward Volume Spin Wave Modes

TL;DR

This study visualizes the dispersion characteristics of backward volume spin wave modes in ferrite films using microwave probing and Fourier analysis, revealing mode splitting and excitation efficiency patterns.

Contribution

It is the first to experimentally visualize the dispersion of the first three backward volume spin wave modes and analyze satellite mode excitation in ferrite films.

Findings

Satellite modes are most effectively excited in the first mode.

Theoretical dispersion matches experimental data for the most excited satellite modes.

Satellite excitation effectiveness decreases with increasing satellite number.

Abstract

Basing on the measurement of spatial spectra (spectra of wavenumbers), the dispersion characteristics of the first three modes of backward volume spin wave, propagating along the direction of a constant uniform magnetic field in a tangentially magnetized ferrite film, were visualized firstly. The study was carried out by microwave probing of spin waves with subsequent use of spatial Fourier analysis of the complex wave amplitude for a series of frequencies. It was found that every m-th mode of the backward volume spins wave can be split into n satellite modes due to the existence of layers with similar magnetic parameters in ferrite film. It was found that satellites of the first mode of this wave are excited most effectively, while satellites of the third mode - least effectively, and the effectiveness of satellites excitation decreases as the number n increases. It is found that the theoretical dispersion dependencies of the first three modes of the wave coincide well with the experimental dispersion dependencies of the satellite mode that are excited most effectively.