Measuring spectrum of spin wave using vortex dynamics

TL;DR

This paper introduces a method to measure magnetic excitation spectra in materials by analyzing vortex lattice dynamics in superconductors, linking vortex motion to magnetic resonance frequencies.

Contribution

It presents a novel transport measurement technique to determine magnetic excitation spectra up to high wave vectors using vortex lattice resonance.

Findings

Resonant vortex motion causes measurable voltage changes.

Magnetic excitation spectra can be extracted from vortex dynamics.

Method allows probing of magnetic excitations up to 10 nm^{-1}.

Abstract

We propose to measure the spectrum of magnetic excitation in magnetic materials using motion of vortex lattice driven by both ac and dc current in superconductors. When the motion of vortex lattice is resonant with oscillation of magnetic moments, the voltage decreases at a given current. From transport measurement, one can obtain frequency of the magnetic excitation with the wave number determined by vortex lattice constant. By changing the lattice constant through applied magnetic fields, one can obtains the spectrum of the magnetic excitation up to a wave vector of order $10\rm{\ nm^{-1}}$.