= Fe, Mn, Cr, Co, and Ni) and their alloys*

Fe₂AlB₂ is one of the promising candidates for magnetic refrigeration technology and has attracted great attention since the recent discovery of its substantial magnetocaloric effect around room temperature. The electronic structure and intrinsic magnetic properties of Fe₂AlB₂-related compounds and their alloys have been investigated using density functional theory. For Fe₂AlB₂, the crystallographic a axis is the easy axis, in agreement with experiment. The magnetic ground state of Mn₂AlB₂ is found to be ferromagnetic in the basal ab plane, but antiferromagnetic along the c axis. All 3d dopants considered decrease the magnetization and Curie temperature in Fe₂AlB₂. Electron doping with Co or Ni has a stronger effect on the decreasing of Curie temperature in Fe₂AlB₂ than hole doping with Mn or Cr. However, a larger amount of Mn doping in Fe₂AlB₂ promotes a ferromagnetic to antiferromagnetic transition. A very anisotropic magnetoelastic effect is found in Fe₂AlB₂: the magnetization has a much stronger dependence on the lattice parameter c than on a or b, which is explained by electronic-structure features near the Fermi level. (Ref: PRB 95, 104427)