It is shown theoretically that an alternating magnetic field applied locally to a stripe periodic heterostructure with different saturation magnetizations, $M_1$ and $M_2$, excites dipolar spin waves, which are able to propagate along the periodicity direction within a narrow frequency band $\left(\Delta \omega /\omega <5\mathrm{\%}\right)$ in the absence of Bragg scattering. A mechanism is found for trapping the out-of-band modes inside a potential well whose formation is mediated by spin pinning at the $M_1/M_2$ interfaces.

• Received 24 September 2010

DOI:https://doi.org/10.1103/PhysRevB.82.172405