Colossal Magnon Magnetoresistance of Two-Dimensional Magnets

TL;DR

This paper reports a colossal magnon magnetoresistance effect in two-dimensional ferromagnets, showing a dramatic change in magnon conductance under magnetic fields, which could advance spintronics applications.

Contribution

It introduces the discovery of a colossal magnon magnetoresistance in 2D magnets and proposes an experimental setup to observe this effect.

Findings

Magnon conductance can change by up to 1000% in a moderate magnetic field.

The CMMR effect depends strongly on magnetic field orientation.

Magnon current in 2D materials is significantly larger than in 3D counterparts.

Abstract

The magnon current holds substantial importance in facilitating the transfer of angular momentum in spin-based electronics. However, the magnon current in three-dimensional magnetic materials remains orders of magnitude too small for applications. In contrast, magnon numbers in two-dimensional systems exhibit significant enhancement and are markedly influenced by external magnetic fields. Here, we investigate the magnon current in a two-dimensional easy-axis ferromagnet and find a colossal magnon magnetoresistance (CMMR) effect, wherein the change of the magnon conductance can reach as high as a thousand percent in a moderate magnetic field. Moreover, the magnitude of the CMMR exhibits significant dependence on the orientation of the magnetic field due to the interplay between magnon- conserving and non-conserving scattering. We propose a non-local magnon-mediated electrical drag experiment for the possible experimental observation of the predicted effect. With the CMMR effect and a much larger magnon number, magnon current in 2D materials shows promise as a primary source for spin transport in spintronics devices.9