Nonvolatile Magnonics in Bilayer Magnetic Insulators

TL;DR

This paper introduces a framework for electrical control of magnons in bilayer 2D magnetic insulators, enabling nonvolatile manipulation of spin excitations and Hall currents through electric fields, with potential for advanced spintronic devices.

Contribution

It presents a novel method to electrically control magnons in bilayer magnetic insulators, including inducing Berry curvature and orbital moments, supported by density-functional-theory calculations.

Findings

Electric field Ez can manipulate magnon properties in bilayer insulators.

Ez induces nonzero Berry curvature and orbital moments of magnons.

Bilayer Cr-based ferromagnets can be engineered for nonvolatile magnon control.

Abstract

Nonvolatile control of spin order or spin excitations offers a promising avenue for advancing spintronics; however, practical implementation remains challenging. In this letter, we propose a general framework to realize electrical control of magnons in 2D magnetic insulators. We demonstrate that in bilayer ferromagnetic insulators with strong spin-layer coupling, electric field Ez can effectively manipulate the spin exchange interactions between the layers, enabling nonvolatile control of the corresponding magnons. Notably, in this bilayer, Ez can induce nonzero Berry curvature and orbital moments of magnons, the chirality of which are coupled to the direction of Ez. This coupling facilitates Ez manipulate the corresponding magnon valley and orbital Hall currents. Furthermore, such bilayers can be easily engineered, as demonstrated by our density-functional-theory calculations on Janus bilayer Cr-based ferromagnets. Our work provides an important step toward realizing nonvolatile magnonics and paves a promising way for future magnetoelectric coupling devices.