A spin current – a flow of spin angular momentum – can be carried either by spin polarized free electrons or by magnons, the quanta of spin waves. Traditionally, it was assumed, that a spin wave in a free magnetic film can transfer energy and angular momentum only along its propagation direction. In this talk, using the data obtained by Brillouin light scattering spectroscopy in combination with an extended theory of dipole-exchange spin-wave spectra, I will show that in obliquely magnetized magnetic films the in-plane propagation of spin waves is accompanied by a transverse spin current without corresponding transverse transport of energy [1]. 

1. D. A. Bozhko, H. Yu. Musiienko-Shmarova, V. S. Tiberkevich, A. N. Slavin, I. I. Syvorotka, B. Hillebrands, and A. A. Serga, Phys. Rev. Research 2, 023324 (2020).