Transient dynamics of strongly coupled spin vortex pairs: effects of anharmonicity and resonant excitation on inertial switching

TL;DR

This paper presents a model system of a two-vortex nanopillar where the resonance frequency can be significantly tuned without high magnetic fields, enabling low-power control of vortex-core switching for GHz oscillators.

Contribution

It introduces a novel method to tune vortex pair resonance frequency over an order of magnitude using low-amplitude, short-duration fields, without high dc magnetic fields.

Findings

Resonance frequency tunability by an order of magnitude.

Low-amplitude, sub-ns field pulses can switch vortex states.

Field anharmonicity and phase control enhance switching performance.

Abstract

Spin vortices in magnetic nanopillars are used as GHz oscillators, with frequency however essentially fixed in fabrication. We demonstrate a model system of a two-vortex nanopillar, in which the resonance frequency can be changed by an order of magnitude, without using high dc magnetic fields. The effect is due to switching between the two stable states of the vortex pair, which we show can be done with low-amplitude fields of sub-ns duration. We detail the relevant vortex-core dynamics and explain how field anharmonicity and phase control can be used to enhance the performance.