Tunneling of spin waves through a magnetic field inhomogeneity

The tunneling mechanism of spin waves through a magnetic field inhomogeneity is investigated by measuring, as well as calculating numerically, the transmission coefficient T as a function of the dc-current (i.e., the barrier width w). Both theoretical and experimental T(w) turned out to be non-exponential. This fact is theoretically explained by the non-local character of the magnetic dipole interaction. This result indicates that spin waves propagating in a magnetic film can pass through a region of a magnetic field inhomogeneity or, alternatively, can be reflected by this region depending on the sign of the inhomogeneity. An optically transparent yttrium-iron garnet (YIG) film is monitored using the time- and space-resolved Brillouin light scattering technique.