Origin of spin reorientation transitions in antiferromagnetic MnPt-based alloys

TL;DR

This study investigates the origins of spin reorientation transitions in MnPt-based antiferromagnetic alloys, revealing how composition and temperature influence magnetic anisotropy through first-principles calculations.

Contribution

The paper provides a detailed first-principles analysis explaining the microscopic mechanisms behind SRTs in MnPt alloys, linking band structure features to magnetic anisotropy changes.

Findings

Concentration and temperature induce SRTs consistent with experiments.

Magnetocrystalline anisotropy is small and highly sensitive to composition and temperature.

Specific band-structure features are responsible for the SRTs.

Abstract

Antiferromagnetic MnPt exhibits a spin reorientation transition (SRT) as a function of temperature, and off-stoichiometric Mn-Pt alloys also display SRTs as a function of concentration. The magnetocrystalline anisotropy in these alloys is studied using first-principles calculations based on the coherent potential approximation and the disordered local moment method. The anisotropy is fairly small and sensitive to the variations in composition and temperature due to the cancellation of large contributions from different parts of the Brillouin zone. Concentration and temperature-driven SRTs are found in reasonable agreement with experimental data. Contributions from specific band-structure features are identified and used to explain the origin of the SRTs.