Possible role of two iron sites in the metamagnetic transition observed in LaFe12 B6

Fixed spin moment calculations within TB-LMTO-ASA method using LSDA were performed for the compound LaFe12 B6 and for lattice constants taken from experimental data. Minima corresponding to the observed low moment and high moment states were found. However, their relative stability is not in agreement with experimental data. Fixed spin moment calculations on model compounds where Fe atoms at either crystallographic sites were replaced by Cu atoms were also performed. It was found that the stability of magnetic moment of Fe atoms at 18(h) site is much more dependent on environment than the stability of magnetic moment of Fe atoms at the 18(g) site.