Effect of Cr on electronic and magnetic properties of χ-carbide (Fe,Cr)5C2

From density function theory calculation, the structural, electronic and magnetic properties of chi-carbides (Fe,Cr)(5)C-2 are investigated. With the increase of Cr content in chi-carbides (Fe,Cr)(5)C-2, the formation energy of chi carbide gradually decrease and energy stability of them increase. The formation energy of Cr5C2 is -0.354 eV/Lu, and the stability of Cr5C2 is higher than other chi carbides (Fe,Cr)(5)C-2, Mn5C2 and Fe5C2. There exists charges transfer from metal cation (Fe/Cr) to C atoms in chi-carbides, and this reveals an ionic contribution to the bonds. The addition of Cr decreases the magnetic moments of chi carbide, and the magnetic moments (Ms) of Cr2Cr2FeC2 and Cr5C2 are 0 mu(B)/f.u., while it expresses opposite magnetic characters of the same atom at different sites in the other chi type (Fe,Cr)(5)C-2 carbides. The 3d states of metal atoms in the majority states (up) move to above the Femi level and some metal atoms (Fe/Cr) in chi type (Fe,Cr)(5)C-2 are undergone the anti-ferromagnetic transformation. (C) 2015 Elsevier B.V. All rights reserved.