Superdirectional Beam of Surface Spin Wave

TL;DR

This paper experimentally and theoretically investigates the diffraction patterns of surface spin waves in ferrite films, demonstrating the possibility of superdirectional beams with minimal spreading and maximal length.

Contribution

It introduces the concept of superdirectional surface spin wave beams in ferrite films and provides experimental validation of their nonexpanding, highly directional nature.

Findings

Superdirectional spin wave beams can have zero angular width.

The beam length can reach approximately 50 mm.

The diffraction pattern depends on transducer orientation and anisotropy.

Abstract

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).