Control of the Bose-Einstein Condensation of Magnons by the Spin-Hall Effect

TL;DR

This paper demonstrates how the spin Hall effect can be used to control the formation of magnon Bose-Einstein condensates in YIG/Pt nanostructures, enabling manipulation of quantum states for spintronic applications.

Contribution

It introduces a novel method to control magnon BEC formation using the spin Hall effect in YIG/Pt structures, affecting the BEC threshold by up to 8%.

Findings

SHE can inject or annihilate magnons depending on current polarity.

Magnon BEC threshold can be tuned by ±8% using SHE.

Control of quantum states is feasible for spintronic devices.

Abstract

Previously, it has been shown that rapid cooling of yttrium-iron-garnet (YIG)/platinum (Pt) nano structures, preheated by an electric current sent through the Pt layer, leads to overpopulation of a magnon gas and to subsequent formation of a Bose-Einstein condensate (BEC) of magnons. The spin Hall effect (SHE), which creates a spin-polarized current in the Pt layer, can inject or annihilate magnons depending on the electric current and applied field orientations. Here we demonstrate that the injection or annihilation of magnons via the SHE can prevent or promote the formation of a rapid cooling induced magnon BEC. Depending on the current polarity, a change in the BEC threshold of -8% and +6% was detected. These findings demonstrate a new method to control macroscopic quantum states, paving the way for their application in spintronic devices.