Magnetic properties of single nanomagnets: EMCD on FePt nanoparticles

TL;DR

This paper demonstrates that with optimized conditions and noise reduction, EMCD can quantitatively measure magnetic properties of individual FePt nanoparticles, specifically determining the orbital to spin magnetic moment ratio.

Contribution

The study shows how to achieve quantitative EMCD measurements on single nanoparticles by combining simulations and noise reduction techniques.

Findings

Orbital to spin magnetic moment ratio for Fe in FePt nanoparticle is 0.08 ± 0.02.

EMCD measurements on single nanoparticles agree with ensemble XMCD results.

Method enables quantitative magnetic characterization at the nanoscale.

Abstract

Energy-loss magnetic chiral dichroism (EMCD) allows for the quantification of magnetic properties of materials at the nanometer scale. It is shown that with the support of simulations that help to identify the optimal conditions for a successful experiment and upon implementing measurement routines that effectively reduce the noise floor, EMCD measurements can be pushed towards quantitative magnetic measurements even on individual nanoparticles. With this approach, the ratio of orbital to spin magnetic moments for the Fe atoms in a single L$1_0$ ordered FePt nanoparticle is determined to be ${m_l}/{m_s} = 0.08 \pm 0.02$. This finding is in good quantitative agreement with the results of XMCD ensemble measurements.