Tight binding prediction of the α-Gd2S3 magnetic structure

Abstract Spin-dependent extended Huckel tight binding (EHTB) calculations were carried out for the magnetic solid Gd 2 S 3 by considering 20 different variations in the ordering of the 4 f 7 moments. The tight-binding calculations are used to interpolate the band structure of a nonmagnetic congener (Y 2 S 3 ) and the 4 f /5 d ,6 s exchange interactions are introduced as perturbations via the introduction of spin-dependent H dd and H ss parameters. The calculations predict that Gd 2 S 3 adopts an antiferromagnetic ordering of the 4 f 7 moments that is consistent with published neutron diffraction results. Our attempt to account for the calculated energies of the spin patterns using an Ising model was unsuccessful.