Antiferromagnetic nano-oscillator in external magnetic fields

TL;DR

This paper analyzes the behavior of an antiferromagnetic nano-oscillator influenced by external magnetic fields, deriving analytical models and validating them with numerical simulations to understand its signal modulation capabilities.

Contribution

It introduces an analytical formula for the interaction between the nano-oscillator and external magnetic fields, supported by numerical simulations for validation.

Findings

Analytical model accurately predicts oscillator response to external fields.

External magnetic fields can modulate the oscillator's output signal.

Numerical simulations agree well with analytical predictions.

Abstract

We describe the dynamics of an antiferromagnetic nano-oscillator in an external magnetic field of any given time distribution. The oscillator is powered by a spin current originating from spin-orbit effects in a neighboring heavy metal layer, and is capable of emitting a THz signal in the presence of an additional easy-plane anisotropy. We derive an analytical formula describing the interaction between such a system and an external field, which can affect the output signal character. Interactions with magnetic pulses of different shapes, with a sinusoidal magnetic field and with a sequence of rapidly changing magnetic fields are discussed. We also perform numerical simulations based on the Landau-Lifshitz-Gilbert equation with spin-transfer torque effects to verify the obtained results and find a very good quantitative agreement between analytical and numerical predictions.