Spin orbit torque nano-oscillators by dipole field-localized spin wave modes

TL;DR

This paper presents a high-quality, tunable spin orbit torque nano-oscillator using dipole field-localized spin wave modes, demonstrating stable operation at room temperature and insights into linewidth behavior influenced by thermal fluctuations.

Contribution

The study introduces a novel approach to confine spin wave modes with a dipole field, enabling tunable, high-quality nano-oscillators for advanced spintronic research.

Findings

Localized modes exhibit narrow linewidth and large amplitude

Oscillator performance persists up to room temperature

Linewidth is proportional to temperature, matching theoretical predictions

Abstract

We demonstrate a high-quality spin orbit torque nano-oscillator comprised of spin wave modes confined by the magnetic field by the strongly inhomogeneous dipole field of a nearby micromagnet. This approach enables variable spatial confinement and systematic tuning of magnon spectrum and spectral separations for studying the impact of multi-mode interactions on auto-oscillations. We find these dipole field-localized spin wave modes exhibit good characteristic properties as auto-oscillators--narrow linewidth and large amplitude--while persisting up to room temperature. We find that the linewidth of the lowest-lying localized mode is approximately proportional to temperature in good agreement with theoretical analysis of the impact of thermal fluctuations. This demonstration of a clean oscillator with tunable properties provides a powerful tool for understanding the fundamental limitations and linewidth contributions to improve future spin-Hall oscillators.