New High-$T_c$ Half-Heusler Ferromagnets NiMnZ (Z = Si, P, Ge, As)

TL;DR

This paper predicts a new class of high-temperature ferromagnetic half-Heusler alloys NiMnZ (Z = Si, P, Ge, As) with potential for spintronics, based on first-principles calculations showing high Curie temperatures and half-metallicity.

Contribution

It introduces a new class of ferromagnetic half-Heusler alloys with high Curie temperatures, supported by first-principles calculations and Monte Carlo simulations.

Findings

Alloys exhibit half-metallicity and ferromagnetism at high temperatures.

Predicted Curie temperatures range from 715K to 1050K.

Alloys are promising for spintronic applications.

Abstract

Based on the first principle calculation, we propose a new class of high-$T_c$ half-heusler ferromagnets NiMnZ (Z = Si, P, Ge, As). The structural and magnetic properties are investigated through the calculation of the electronic structure, phase stability, equilibrium lattice constant, magnetic exchange interaction $J_{ij}$ and Curie temperature $T_c$. It is found that all alloys show half-metallicity and ferromagnetism at temperatures much higher than room temperature in a wide range of lattice expansion (compression). At the equilibrium lattice constant, $T_c$ of 715K, 840K, 875K and 1050K are predicted by Monte Carlo simulation for NiMnP, NiMnAs, NiMnGe and NiMnSi, respectively. Following these results, these alloys are strongly expected to be promising candidates for spintronic applications.