Enhancement in magnetic parameters of L10-FeNi on Pd-substitution for permanent magnets

In order to analyze the effect of Pd substitution on the overall electronic and magnetic properties of L1(0)-FeNi, ab-initio calculations have been performed using density functional theory (DFT) approach within generalized gradient approximation. The magnetocrystalline anisotropy for pristine FeNi is low (< 0.5 MJ/m(3)). A slight increase in its MCA is observed with single/dual substitution of Pd (from 0.430 to 0.562/0.616 MJ/m(3)) as a consequence of complex spin-orbit coupling of 4d transition element, Pd. In the nutshell, the presence of 4d-element (Pd) at Fe or/and Ni sites (except FeNi:Pd-Ni case in which Pd substitutes only Ni) improves all the magnetic parameters including maximum energy product of L1(0)-FeNi by appreciable amounts. In all these cases, the minimum requirement for permanent magnets, which is H-c > M-s/2 and kappa > 1/2, is found to be achieved. Consequently, the Pd-substituted FeNi alloys become the potential materials for rare-earth free permanent magnets.