Observation of Magnetic Supercooling of the Transition to the Vortex State

TL;DR

This paper reports the observation of magnetic supercooling during the transition to the vortex state in nanomagnetic disks, suggesting a first-order phase transition description, using nanomechanical torque magnetometry.

Contribution

It provides experimental evidence of magnetic supercooling in nanodisks and introduces a novel measurement technique to observe single vortex events.

Findings

Evidence of magnetic supercooling in nanodisks

Transition described as a modified first-order phase transition

Single vortex creation observed without averaging

Abstract

We demonstrate that the transition from the high-field state to the vortex state in a nanomagnetic disk shows the magnetic equivalent of supercooling. This is evidence that this magnetic transition can be described in terms of a modified Landau first-order phase transition. To accomplish this we have measured the bulk magnetization of single magnetic disks using nanomechanical torsional resonator torque magnetometry. This allows observation of single vortex creation events without averaging over an array of disks or over multiple runs.