Electronic and magnetic properties ofFeBr2

Abstract

Electronic and magnetic properties of ${\mathrm{FeBr}}_{2}$ have been surprisingly well described as originating from the ${\mathrm{Fe}}^{2+}$ ions and their fine electronic structure. The fine electronic structure has been evaluated by taking into account the spin-orbit coupling, crystal-field and intersite spin-dependent interactions. The large magnetic moment of iron, of $4.4{\ensuremath{\mu}}_{B},$ can be theoretically derived provided the spin-orbit coupling is explicitly taken into account. These calculations show that for the meaningful analysis of properties of ${\mathrm{FeBr}}_{2}$ the spin-orbit coupling is essentially important and that the orbital moment $(0.74{\ensuremath{\mu}}_{B})$ is largely unquenched (by the off-cubic trigonal distortion in the presence of the spin-orbit coupling).