Lattice constants and magnetism of L10-ordered FePt under high pressure

TL;DR

This study combines first-principles calculations and synchrotron x-ray experiments to explore how high pressure affects the lattice structure and magnetism of L10-ordered FePt, revealing anomalies and potential for novel magnetic states.

Contribution

It provides the first combined theoretical and experimental analysis of pressure-induced changes in lattice and magnetic properties of FePt, identifying specific pressure points of interest.

Findings

c/a ratio shows anomaly at ~20 GPa

Pt magnetic moment sharply suppressed at ~60 GPa

no significant change in Pt magnetic moment up to 20 GPa

Abstract

We studied the relationship between the lattice constant and magnetism of L10-ordered FePt under high pressure by means of first-principles calculations and synchrotron x-ray measurements. Based on our calculations, we found that the c/a ratio shows an anomaly at ~ 20 GPa and that the Pt magnetic moment is sharply suppressed at ~ 60 GPa. As for the c/a, we experimentally verified the anomaly at ~ 20 GPa by powder x-ray diffraction. We also measured the x-ray magnetic circular dichroism at the Pt L edge up to ~ 20 GPa. Any significant change of the Pt magnetic moment was not observed, in agreement with the calculations. These results thus indicate the possibility that novel magnetic states can be created in L10-ordered FePt by lattice deformation under high pressure.