An Experiment-Based Numerical Treatment of Spin Wave Modes in Periodically Porous Materials

To determine a general correlation between structure and dynamic magnetic properties of porous materials, the frequencies of magnetic spin waves are studied by Brillouin light scattering from nickel inverse opals and backed up by micromagnetic simulations. Within the observed unit cell size regime between 400 and 800 nm, discrete thickness standing modes are found to change with unit cell size. By applying pair correlation functions of the inverse opal solid phase normal to the applied field to an equation for perpendicular standing modes, the directional and unit cell size-dependent spectral intensities above the surface mode region can be traced. Thus, an accessible general approach for the prediction of standing spin waves in porous materials is obtained.