Influence of the rare-earth site nonstoichiometry and Mn doping on the electronic structure of TbNi2

Abstract Electronic structure and magnetic properties of Tb 1− δ Ni 2 Mn x alloys ( δ =0, 0.04 and 0≤ x ≤1) are investigated within the Coherent Potential Approximation (CPA) taking into account the strong electronic correlations ( U ) in Tb f -shell and the spin–orbit coupling (SO) in f -Tb, d -Ni, and d -Mn shells. Explicit consideration of electronic correlations and spin–orbit coupling is necessary for correct description of f -levels positions in the spectrum. Both vacancy in Tb site and manganese impurity in Tb and Ni sites cause the decrease of the total magnetic moment value J keeping its direction [111]. The absolute value of | J | decreases linearly with the increase of Mn impurity concentration; the ratio of | J |(Tb 0.96 Ni 2 Mn 1 )/| J |(Tb 0.96 Ni 2 ) is 0.66 which agrees well with experiment.