Superdirectional Beam of Surface Spin Wave
  The visualized diffraction patterns of surface spin wave excited by arbitrarily oriented linear transducer are investigated experimentally in the plane of tangentially magnetized ferrite film for the case where the transducer length D is much larger than the wavelength L. It is shown experimentally and theoretically that the angular width of diffracted surface spin wave beam in anisotropic ferrite film can take values greater or less than L/D and can also be zero. For the last case superdirectional (nonexpanding) beam of the surface spin wave is observed experimentally: the smearing of the beam energy along the film plane is absent and the length of the beam trajectory is maximal (~50 mm). 
A.Yu. Annenkov, S.V. Gerus and E.H. Lock
physics.optics