Orbital and spin moments in SmFe₂ studied by means of white-x-ray magnetic diffraction

A magnetic structure of SmFe₂ with a Laves phase crystalline structure was investigated by means of white-x-ray magnetic diffraction. The orbital and the spin magnetic form factors of Sm and Fe ions have been obtained as a function of momentum transfer. Their extrapolation to zero momentum transfer, according to the dipole approximation based on an atomic model, has given the values of the spin and the orbital magnetic moments of Sm ions as -2.54 ± 0.55 μ_B and 2.79 ± 0.61 μ_B, respectively. This result confirms that the small magnetic moment of Sm ions arises from antiparallel coupling between the spin and the orbital magnetic moments. The spin and the orbital magnetic moments of Fe ions have been also estimated, as 1.13 ± 0.25 μ_B and 0.19 ± 0.04 μ_B, respectively.