Electrical measurement of antivortex wall eigenfrequency

TL;DR

This paper experimentally investigates the eigenfrequency of ferromagnetic antivortex walls using electrical methods, revealing multiple eigenmodes, nonlinear behaviors, and coexistence of spin wave excitations in nanostructures.

Contribution

It introduces electrical measurement techniques for antivortex eigenfrequency and reports the first direct frequency domain observation of antivortex nucleation.

Findings

Identification of multiple eigenmodes in antivortex walls

Observation of nonlinear behaviors at large excitation amplitudes

Coexistence of antivortex gyration and spin wave excitations

Abstract

The dynamics of a ferromagnetic antivortex wall has been experimentally studied in a magnetic nanostructure. Two different techniques have been used to independently measure the eigenfrequency of an antivortex wall such as the resonance excitation by sinusoidal microwave and the damped resonance excitation induced by short voltage pulses. Direct observation of antivortex wall nucleation has been measured in the frequency domain for the first time. Electrical measurements of the antivortex dynamics in frequency domain reveal the existence of multi-eigenmodes as well as nonlinear behaviors for large excitation amplitudes. The time resolved measurements of the antivortex wall show that the frequency of the damped gyration is similar to that of frequency domain and coexistence of spin wave excitations.