Phase stability and magnetic properties of B2 and L1₀ PtMn_1-XFe_X alloys: a cluster expansion and ab initio approach

¹ Advanced Materials Division, MINTEK, South Africa
² Materials Modelling Centre, University of Limpopo, South Africa

^* Corresponding author: ram@mintek.co.za

Abstract

MnPt-based alloys are promising new materials for magnetic recording and spintronic applications due to their interesting magnetic properties. The underlying thermodynamic properties are still unclear, despite numerous efforts to improve ferromagnetic stability through alloying. In this work, the phase stability of B2 and L1₀ PtMn_1-xFe_x alloys is investigated using a combination of density functional theory (DFT) and Cluster Expansion (CE). CE model accuracy is evaluated against DFT data, where cross-validation scores were found to be reasonable. The CE generated 16 and 27 new structures on B2 and L1₀ PtMn_1-xFe_x, respectively. The ground state line predicted 6 stable structures with negative formation energies for both B2 and L1₀ PtMn_1-xFe_x alloys, suggesting thermodynamic stability. Furthermore, the magnetic strength of the ground state structures is evaluated using DFT.