Magnetoelectricity induced by rippling of magnetic nanomembranes and wires

TL;DR

This paper demonstrates that nanoscale rippling and geometric deformation in magnetic nanostructures can induce linear magnetoelectric coupling in insulators with ferromagnetic ground states, offering a new approach to magnetoelectric effects.

Contribution

It introduces a novel method to generate magnetoelectric coupling through structural deformation in simple ferromagnetic insulators, bypassing complex magnetic textures.

Findings

Rippling induces magnetoelectric multipoles in 2D magnets.

Zig-zag ferromagnetic wires exhibit a magnetic toroidal moment.

Structural deformation activates magnetoelectric monopoles.

Abstract

Magnetoelectric crystals have the interesting property that they allow electric fields to induce magnetic polarizations, and vice versa, magnetic fields to generate ferroelectric polarizations. Having such a magnetoelectric coupling usually requires complex types of magnetic textures, e.g., of spiralling type. Here we establish a novel approach to generate a linear magnetoelectric coupling in insulators with a conventional, ferromagnetic ground state. We show that nanoscale curved geometries lead to a reorganization of the magnetic texture that spontaneously breaks inversion symmetry and thereby induces macroscopic magnetoelectric multipoles. Specifically, we prove that structural deformation in the form of controlled ripples activate a magnetoelectric monopole in the recently synthesised two-dimensional magnets. We also demonstrate that in zig-zag shaped ferromagnetic wires in planar architectures, a magnetic toroidal moment triggers a direct linear magnetoelectric coupling.