Spin waves turning a corner

We studied the propagation of spin waves in a Ni ₈₁Fe ₁₉ micro-waveguide comprising a smooth, S-shaped bend using Brillouin light scattering microscopy. A direct current flowing through a gold wire underneath the Ni ₈₁Fe ₁₉ provides a local magnetic field, which maintains a transverse magnetization around the bend of the waveguide. It is demonstrated that spin-wave propagation inside the bend can be realized in contrast to the case of an externally applied magnetic field, which generates strong inhomogeneities in the internal effective field distribution, preventing any spin-wave propagation across the bend.