Mode beating of spin wave beams in ferrimagnetic Lu/sub 2.04/Bi/sub 0.96/Fe/sub 5/O/sub 12/ films

We report on measurements of the two-dimensional intensity distribution of linear and non-linear spin wave excitations in a LuBiFeO film. The spin wave intensity was detected using a high-resolution Brillouin light scattering spectroscopy setup. The observed snake-like structure of the spin wave intensity distribution is understood as a mode beating between modes with different lateral spin wave amplitude distributions. The theoretical treatment of the linear regime is performed analytically, whereas the propagation of non-linear spin waves is simulated by a numerical solution of a non-linear Schrodinger equation with suitable boundary conditions.