Electronic structure and spin polarization of Fe$_{1-x}$Mn(Co,Ni)$_x$S$_2$ alloys from first principles

TL;DR

This study uses first-principles calculations to explore how alloying FeS$_2$ with Mn, Co, or Ni affects electronic structure and spin polarization, identifying potential half-metallic candidates for spintronics.

Contribution

It provides a systematic first-principles analysis of FeS$_2$ alloys with Mn, Co, and Ni, revealing new candidates for half-metallicity and spin state transitions.

Findings

Co-doped alloys are half-metallic across all concentrations.

High Mn concentration alloys are promising for spintronics.

Low Ni concentration alloys show potential for half-metallicity.

Abstract

Alloying effects by T=Mn,Co,Ni-substitution on FeS$_2$ have been investigated using density-functional calculations. The ferromagnetic alloys Fe$_{1-x}$T$_x$S$_2$ have been investigated for concentrations $x=\frac{1}{4},\frac{1}{2},\frac{3}{4}$ together with the ground states of the pure compounds. The electronic structure is discussed with the goal to identify candidates for half metals, which are of interest for spintronics applications. We find interesting candidates at high concentration of the Mn-doped FeS$_2$ and at low concentrations for Ni-doped materials. For the Mn alloys we also note the proximity to a low-spin to high spin transition. For Co-doped materials we reproduce the well known finding of half metallicity over the entire concentration range.