Effects of Electron Correlations on the Magnetic Stability of Rh2TMSn Full Heusler Alloys (TM=Cr, Mn, and Fe)

Abstract

First-principles total energy calculations were performed to study the stability of Rh2TMSn (TM=Cr, Mn and Fe) toward different magnetic ordering, ferromagnetic (FM), antiferromagnetic type I (AFM-I) and antiferromagnetic type II (AFM-II). We studied the effects of electron correlation on the magnetic stability of the compounds in both cubic and tetragonal structures using density functional theory (DFT) within the generalized gradient approximation (GGA) and GGA+U. The results show that the electron correlation has an important role in determining the magnetic stability of the compounds. The magnetic stability obtained from GGA+U agrees well with the available experimental results. The thermodynamic stability of the three compounds shows that all the compounds are stable in both cubic and tetragonal structures. Using the energy difference method, we were able to calculate the exchange interactions and estimate the Curie temperature of the Rh2MnSn compound in the cubic structure. The phonon dispersion curves were investigated for the first time using the linear-response approach in the context of density functional perturbation theory. The results show that all the compounds are dynamically stable in their predicted phases