Possible spin gapless semiconductor type behaviour in CoFeMnSi epitaxial thin films

TL;DR

This paper reports the successful fabrication and characterization of epitaxial CoFeMnSi thin films exhibiting properties consistent with spin-gapless semiconductors, highlighting their potential for spintronics.

Contribution

It demonstrates the growth of high-quality epitaxial CoFeMnSi thin films with spin-gapless semiconductor behavior on MgO substrates.

Findings

Epitaxial growth with smooth crystalline surface achieved

Ferromagnetic behavior with Curie temperature above 400 K

Electrical conductivity shows nearly temperature-independent semiconducting behavior

Abstract

Spin-gapless semiconductors with their unique band structures have recently attracted much attention due to their interesting transport properties that can be utilized in spintronics applications. We have successfully deposited the thin films of quaternary spin-gapless semiconductor CoFeMnSi Heusler alloy on MgO (001) substrates using a pulsed laser deposition system. These films show epitaxial growth along (001) direction and display uniform and smooth crystalline surface. The magnetic properties reveal that the film is ferromagnetically soft along the in-plane direction and its Curie temperature is well above 400 K. The electrical conductivity of the film is low and exhibits a nearly temperature independent semiconducting behaviour. The estimated temperature coefficient of resistivity for the film is -7x10^-10 Ohm.m/K, which is comparable to the values reported for spin-gapless semiconductors.