Direct imaging of spin wave emission from magnetic vortex cores

Spin wave phenomena are an intensely studied field of magnetism, ranging from fundamental magnonics to the proposal of spin wave applications in logic or oscillator devices. In particular, the propagation of nanoscopic spin waves has come into the fore. Typically, micro-striplines or point- contacts are used to generate such spin waves in ferromagnetic media. However, a real-space observation of nanoscopic spin wave propagation has not been reported yet. Here we present the direct imaging of spin wave propagation as well as a novel concept for their generation based on the dynamics of interlayer coupled vortex pairs.