Non-collinear magnetism contra frustration: Magnetic order and anisotropy in hexagonal MnPtGa

Abstract

MnPtGa is a hexagonal intermetallic compound with a rich variety of magnetic order. Its magnetic state is reported to range from collinear ferromagnetism, to non-collinear skyrmion type order. MnPtGa is a system with strongly localized magnetic moments at the Mn atoms as was demonstrated using calculations for disordered local moments. The magnetic moments at the Mn sites stay at about 3.9 bohr even above the calculated magnetic transition temperatures (TN = 220 K or TC = 285 K). In the present work, a special emphasis was focused on the possible non-collinear magnetic order using first principles calculations. The investigations included magnetic anisotropy, static noncollinear order in form of spin canting and dynamic non-collinearity in spin spirals. It is found that the energy differences between ferromagnetic, antiferromagnetic, canted, or spiral magnetic order are in the order of not more than 30 meV, which is in the order of thermal energies at ambient temperature. This hints that a particular magnetic state - including skyrmions, antiskyrmions or spin glass transitions - may be forced when an external field is applied at finite temperature.

References in corpus (6)

• Calculated electronic and magnetic properties of the half-metallic, transition metal based Heusler compounds
• Heisenberg and anisotropic exchange interactions in magnetic materials with correlated electronic structure and significant spin-orbit coupling
• Ab initio analysis of magnetic properties of prototype B20 chiral magnet FeGe
• An accurate scheme to calculate the interatomic Dzyaloshinskii-Moriya interaction parameters
• Phase transition in the magnetocrystalline anisotropy of tetragonal Heusler alloys: Rh${}_{2}T$Sb, $T=$ Fe, Co
• Unveiling the interplay of magnetic order and electronic band structure on the evolution of anomalous Hall effect in MnPtGa single crystal