Stabilization of helical magnetic structures in thin multilayers

TL;DR

This paper reports the discovery of a stable helical magnetic structure in thin multilayers, stabilized by internal exchange and anisotropy fields, with potential applications in energy storage and spintronic devices.

Contribution

It introduces a novel stable helical magnetic state in multilayer films, characterized by internal fields and exchange interactions, confirmed through micromagnetic simulations.

Findings

Helical structure is stable without external magnetic field.

Distinct resonance frequencies enable easy experimental detection.

Potential for energy storage in spin-based nanodevices.

Abstract

Based on micromagnetic simulations, we report on a novel helical magnetic structure in a soft magnetic film that is sandwiched between and exchange-coupled to two hard magnetic layers. Confined between antiparallel hard magnetic moments, a helix with a turn of 180$^{\circ}$ is stable without the presence of an external magnetic field. The magnetic stability is determined by the energy minimization and is a result of an internal field created by exchange interaction and anisotropy. Since the internal field stores magnetic energy, the helix can serve as an energy-storing element in spin-based nanodevices. Due to the significantly different magnetic resonance frequencies, the ferromagnetic and helical ground states are easy to distinguish in a broadband ferromagnetic resonance experiment.