Magnetoelastic effects in doped Fe2P

TL;DR

This study combines neutron diffraction and DFT calculations to analyze magnetoelastic effects in doped Fe2P, revealing structural changes at the Curie temperature and how doping influences magnetic moments and electronic structure.

Contribution

It provides new insights into the magneto-elastic coupling and dopant site preferences in Fe2P using combined experimental and theoretical approaches.

Findings

Basal plane contracts on heating through TC

Doping increases FeI magnetic moments

Structural changes affect electronic band structure

Abstract

We use combine high resolution neutron diffraction (HRPD) with density functional theory (DFT) to investigate the exchange striction at the Curie temperature (TC) of Fe2P and to examine the effect of boron and carbon doping on the P site. We find a significant contraction of the basal plane on heating through TC with a simultaneous increase of the c-axis that results in a small overall volume change of ~0.01%. At the magnetic transition the FeI-FeI distance drops significantly and becomes shorter than FeI-FeII . The shortest metal-metalloid (FeI-PI) distance also decreases sharply. Our DFT model reveals the importance of the latter as this structural change causes a redistribution of the FeI moment along the c-axis (Fe-P chain). We are able to understand the site preference of the dopants, the effect of which can be linked to the increased moment on the FeI-site, brought about by strong magneto-elasticity and changes in the electronic band structure.