Transverse spin currents carried by surface spin waves in obliquely magnetized magnetic films

Properties of spin waves (SWs) are well-studied in perpendicular and in-plane magnetized magnetic films, but are understood much worse in the case of oblique magnetization (OM). Recent studies [1, 2] show an unexpected and interesting effect in OM films, namely, an appearance of transverse spin currents (TSCs) carried by SWs propagating in the backward-volume-type geometry. Here, we theoretically study this effect for surface SWs propagating approximately perpendicularly to the bias magnetic field (Damon-Eschbach-type geometry). We show, that the TSC resonantly depends on the direction of SW propagation, reaching maximum when SWs propagate several degrees away from the normal to the bias field. The maximum TSC of surface SWs significantly exceeds that of volume SWs, which makes surface SWs preferable for experimental study of TSCs.

[1] D. Bozhko et al., “Wavelength-dependent transformation of dipole-exchange magnon modes in obliquely magnetized YIG films”, CD-10, MMM-2017 (Pittsburgh, USA, Nov. 2017).
[2] H. Musiienko-Shmarova et al., “Dipolar-exchange magnon and phonon spectra in arbitrarily magnetized yttrium-iron-garnet films”, Magnonics-2017 (Oxford, England, Aug. 2017).