The electronic structure and magnetic properties of full Heusler alloy Mn₂CrAl

The full Heusler alloys Mn₂MeZ, where Me is a 3d-metal and Z – an element of group III–V, attract the attention of researchers as materials promising for magnetoelectronic and thermoelectric applications [1]. These alloys may exhibit strong ferromagnetism or compensated ferrimagnetism up to high temperatures, phase transitions with a change in the magnetic structure are possible [2]. The magnetic measurements for the Mn₂YAl systems (Y = Cr, Mn, Fe) give zero total magnetization and may indicate compensated ferrimagnetism [2]. This work presents the results of calculations of the electronic structure and magnetic properties of two different phases of the Heusler alloy Mn₂CrAl. The first one is the cubic Fm-3m (space group 225) L2₁-type structure. The electronic structure of the Mn₂CrAl alloy was computed within GGA(+U) approaches. The latter method was used to take into account electron correlations in the Mn 3d shell for the value of Coulomb parameter ranging from 1 to 6 eV and the exchange (Hund) parameter equal to 0.86 eV. In our calculations, it was found that the electronic structure of Mn₂CrAl is metallic similar to Mn₂NiAl [3], and has a ferrimagnetic ordering of manganese atoms. The second phase of Mn₂CrAl is the cubic P4₁32 (space group 213) β-Mn-type one, which was also found to have a ferrimagnetic ordering with low values of moments of individual ions and the total moment equal to 0.12 µ_B/f.u. [4]. Thus, the calculated magnetic properties of the β-Mn-type phase of Mn₂CrAl are consistent with the experimental results [2], according to which the magnetization of this compound is close to zero.

The research was supported by the Russian Science Foundation, project no. 22-22-20109.

[1] C.Felser et al., APL Mater. 3, 041518 (2015).

[2] V.V.Marchenkov et al., JETP 155, 1083 (2019).

[3] E.D.Chernov et al., Magnetochemistry 9, 185 (2023).

[4] E.I.Shreder et al., Phys. Met. Metallogr. 124, 7 (2023).