Ab initio Prediction of Mechanical, Electronic, Magnetic and Transport Properties of Bulk and Heterostructure of a Novel Fe-Cr based Full Heusler Chalcogenide

TL;DR

This study uses density functional theory to predict the structural, electronic, magnetic, and transport properties of a novel Fe-Cr based full Heusler chalcogenide, Fe$_2$CrTe, in bulk and heterostructure forms, revealing high spin polarization and potential for spintronic applications.

Contribution

First comprehensive ab initio analysis of Fe$_2$CrTe's properties, including stability, magnetic behavior, and tunneling magnetoresistance, in both cubic and tetragonal phases.

Findings

Fe$_2$CrTe exhibits ferromagnetic half-metallicity with 95% spin polarization.

Tetragonal phase shows ferrimagnetic metallic behavior with similar energy to cubic phase.

High tunneling magnetoresistance ratio of 1000% in tetragonal phase.

Abstract

Using electronic structure calculations based on density functional theory, we predict and study the structural, mechanical, electronic, magnetic and transport properties of a new full Heusler chalcogenide, namely, Fe$_2$CrTe, both in bulk and heterostructure form. The system shows a ferromagnetic and half-metallic(HM) like behavior, with a very high (about 95%) spin polarization at the Fermi level, in its cubic phase. Interestingly, under tetragonal distortion, a clear minimum (with almost the same energy as the cubic phase) has also been found, at a c/a value of 1.26, which, however, shows a ferrimagnetic and fully metallic nature. The compound has been found to be dynamically stable in both the phases against the lattice vibration. The elastic properties indicate that the compound is mechanically stable in both the phases, following the stability criteria of the cubic and tetragonal phases. The elastic parameters unveil the mechanically anisotropic and ductile nature of the alloy system. Due to the HM-like behavior of the cubic phase and keeping in mind the practical aspects, we probe the effect of strain as well as substrate on various physical properties of this alloy. Transmission profile of the Fe$_2$CrTe/MgO/Fe$_2$CrTe heterojunction has been calculated to probe it as a magnetic tunneling junction (MTJ) material in both the cubic and tetragonal phases. Considerably large tunneling magnetoresistance ratio (TMR) of 1000% is observed for the tetragonal phase, which is found to be one order of magnitude larger than that of the cubic phase.