Jahn-Teller like origin of the tetragonal distortion in disordered Fe-Pd magnetic shape memory alloys

TL;DR

This study uses density functional theory to reveal that a Jahn-Teller like effect causes tetragonal distortion in disordered Fe-Pd magnetic shape memory alloys, explaining experimental magnetization data.

Contribution

It identifies the Jahn-Teller like effect as the origin of tetragonal distortion in Fe-Pd alloys, providing insight into their structural and magnetic properties.

Findings

Jahn-Teller like effect drives tetragonal distortion.

Calculations match experimental magnetization data.

Potential for property optimization with third elements.

Abstract

The electronic structure and magnetic properties of disordered Fe$_{x}$Pd$_{100-x}$ alloys $(50 < x < 85)$ are investigated in the framework of density functional theory using the full potential local orbital method (FPLO). Disorder is treated in the coherent potential approximation (CPA). Our calculations explain the experimental magnetization data. The origin of the tetragonal distortion in the Fe-Pd magnetic shape memory alloys is found to be a Jahn-Teller like effect which allows the system to reduce its band energy in a narrow composition range. Prospects for an optimization of the alloys' properties by adding third elements are discussed.