Effect of Electron Correlations on the Electronic Structure and Magnetic Properties of the Full Heusler Alloy Mn2NiAl

In this theoretical study, we investigate the effect of electron correlations on the electronic structure and magnetic properties of the full Heusler alloy Mn2NiAl in the framework of first-principles calculations. We investigate the electron correlation effect as employed within hybrid functional (HSE) and also within the DFT+U method with varied values of parameters between 0.9 and 6 eV. The XA-crystal structure was investigated with antiferromagnetic orderings of the magnetic moments of the manganese. It was found that with a growth of the Coulomb interaction parameter, the manganese ions magnetic moment increases, and it reaches the value of 4.15-4.46 mu(B) per Mn. In addition, the total magnetic moment decreases because of the AFM ordering of the Mn ions and a small magnetic moment of Ni. The calculated total magnetic value agrees well with recent experiments demonstrating a low value of magnetization. This experimental value is most closely reproduced for the moderate values of the Coulomb parameter, also calculated in constrained LDA, while previous DFT studies substantially overestimated this value. It is also worth noticing that for all values of the Coulomb interaction parameter, this compound remains metallic in its electronic structure in agreement with transport measurements.

Automated summary

In this theoretical study, the effect of electron correlations on the electronic structure and magnetic properties of Mn2NiAl alloy was investigated using first-principles calculations. Hybrid functional (HSE) and DFT+U methods were employed to study the electron correlation effect with a range of parameter values. The results showed that the manganese ions' magnetic moment increased with an increase in the Coulomb interaction parameter, while the total magnetic moment decreased due to antiferromagnetic ordering of the Mn ions and small magnetic moment of Ni. The calculated total magnetic moment agreed well with experimental results, and the compound remained metallic in its electronic structure.