Room temperature tetragonal noncollinear antiferromagnet Pt$_2$MnGa

TL;DR

This paper reports the discovery and analysis of a tetragonal noncollinear antiferromagnet Pt$_2$MnGa, stable up to 350 K, with a helical spiral magnetic order potentially useful for non-volatile magnetic memory.

Contribution

It introduces a new Heusler compound with a stable helical spiral magnetic order and explains its origin through ab-initio calculations, highlighting its potential for memory applications.

Findings

Helical spiral magnetic order stable up to 350 K.

The spiral is stabilized by large basal plane magnetocrystalline anisotropy.

Potential for helicity switching in magnetic memory devices.

Abstract

Here we present the tetragonal stoichiometric Heusler compound Pt$_2$MnGa with the noncollinear AFM order stable up to 350 K. It is resolved by the neutron diffraction as a helical spiral propagating along the tetragonal axis. Ab-initio calculations suggest a pure exchange origin of the spiral and explain its helical character being stabilized by a large basal plane magnetocrystalline anisotropy (MCA). Together with the inversion-symmetric crystal structure, this provides a bi-stability of a spiral with respect to the right- and left-handed magnetic helices. Despite the large MCA, the long period of a helix might greatly facilitate the switch of the helicity by the precessional reorientation, suggesting Pt$_2$MnGa as a potential candidate for the vector-helicity based non-volatile magnetic memory.