Peculiarities of electronic transport and magnetic state in half-metallic ferromagnetic and spin gapless semiconducting Heusler alloys

TL;DR

This paper reviews experimental and theoretical studies on Heusler alloys, highlighting their electronic transport and magnetic properties, and discusses the potential existence of half-metallic ferromagnetic and spin gapless semiconducting states.

Contribution

It provides a comprehensive survey of Heusler alloys, identifying their electronic and magnetic behaviors, and suggests the presence of HMF and spin gapless semiconductor states in specific compositions.

Findings

Co₂FeZ alloys show properties of conventional ferromagnets.

Fe₂YAl and Mn₂YAl alloys exhibit metallic and semiconducting characteristics.

Magnetic properties change from ferromagnetic to ferrimagnetic with composition variation.

Abstract

A brief survey of experimental and theoretical studies of half-metallic ferromagnets (HMFs) and spin gapless semiconductors is given, the possible candidates being the X$_2$YZ (X = Mn, Fe, Co; Y = Ti, V, Cr, Mn, Fe, Co, Ni; Z = Al, Si, Ga, Ge, In, Sn, Sb) Heusler alloys. The data on the electrical resistivity, normal and anomalous Hall Effect, and magnetic properties are presented. It is shown that the Co$_2$FeZ alloys demonstrate properties of conventional ferromagnets, the HMF properties being also manifested at the variation of the Z-component. The Fe$_2$YAl and Mn$_2$YAl alloys show at the variation of the Y-component both metallic and semiconducting electronic characteristics, the magnetic properties, changing from the ferromagnetic to compensated ferrimagnetic state. The HMF and spin gapless semiconductor states are supposed to exist in these Heusler alloys systems.