Observation of droplet soliton drift resonances in a spin-transfer-torque nanocontact to a ferromagnetic thin film

TL;DR

This paper reports the observation of droplet soliton drift resonances at room temperature in a spin-transfer-torque nanocontact, explaining their reduced stability compared to low-temperature conditions.

Contribution

It provides experimental evidence and micromagnetic simulations revealing the origin of droplet soliton drift instabilities at room temperature.

Findings

Detection of droplet soliton drift resonances at room temperature.

Identification of effective field asymmetry as the cause of drift instability.

Explanation of reduced droplet soliton stability at room temperature.

Abstract

Magnetic droplet solitons are non-linear dynamical modes that can be excited in a thin film with perpendicular magnetic anisotropy with a spin-transfer-torque. Although droplet solitons have been proved to be stable with a hysteretic response to applied currents and magnetic fields at low temperature, measurements at room temperature indicate less stability and reduced hysteresis width. Here, we report evidence of droplet soliton drift instabilities, leading to drift resonances, at room temperature that explains their lower stability. Micromagnetic simulations show that the drift instability is produced by an effective field asymmetry in the nanocontact region that can have different origins.