All-Angle Collimation for Spin Waves

TL;DR

This paper investigates the phenomenon of spin wave collimation at interfaces between different magnetic materials, revealing conditions under which spin waves can be directed with minimal divergence across various angles.

Contribution

It introduces a comprehensive analysis of spin wave refraction and collimation in both homogeneous and patterned magnetic systems using theoretical and simulation methods.

Findings

Collimation observed in Co and Py due to intrinsic anisotropy.

All-angle collimation achieved in homogeneous and patterned YIG systems.

Refraction analyzed via isofrequency contours and micromagnetic simulations.

Abstract

We studied the effect of collimation for monochromatic beams of spin waves, resulting from the refraction at the interface separating two magnetic half-planes. The collimation was observed in broad range of the angles of ncidence for homogenous Co and Py half-planes, due to significant intrinsic anisotropy of spin wave propagation in these materials. The effect exists for the sample saturated by in plane magnetic field tangential to the interface. The collimation for all possible angles of incidence was found in the system where the incident spin wave is refracted on the interface between homogeneous and periodically patterned layers of YIG. The refraction was investigated by the analysis of isofrequency dispersion contours of both pairs materials, i.e., uniform YIG/patterned YIG and Co/Py, which are calculated with the aid of the plane wave method. Besides, the refraction in Co/Py system was studied using micromagnetic simulations.