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

Abstract

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 μB 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.

Magnetic States and Electronic Properties of Manganese-Based Intermetallic Compounds Mn2YAl and Mn3Z (Y = V, Cr, Fe, Co, Ni; Z = Al, Ge, Sn, Si, Pt)

“…Table 1 presents information on Mn 2 YZ and Mn 3 Z (Y = Cr, Fe, Co; Z = Al, Ge, Si, Sn, Pt), for which the electronic state, magnetic state, and anomalous Hall conductivity are given. Mn 2 VSi HMF [41] FIM [41] Mn 2 CrAl HMF [90,91] CFIM 3 [21] Mn 2 FeAl HMF [36] CFIM [42] Frustrated AFM 4 [44] Mn 2 NiAl AFM [92] Mn 2 CoAl SGS 5 [46] FM 6 [46] 21.8 [46] Mn 3 Al HM-AFM 7 [93] CFIM (cast); frustrated AFM (RMQ) 8 [28,29] AFM [93] 320 [61] Mn 3 Ge HM-FIM 9 [93] TSM 10 [9] FIM [93] Noncollinear AFM [9,62] 60 at RT; ~380 at 5 K [62] Mn 3 Si HM-FIM [93] FIM [93] Mn 3 Sn TSM [78] Noncollinear AFM [77,80] kagome AFM [78] ~20 at RT; ~100 at 100 K [94] Mn 3 Pt TSM [81] kagome AFM [81] 100 [81] Mn 3 Ir AFM [95] 40 at RT [95] 1 HMF is a half metallic ferromagnet. 2 FIM is a ferrimagnet.…”