Local magnetic anisotropy of the rare-earth elements in iron-containing oxypnictides RFeAsO (R = Сe, Nd, Sm)
O.V. Gornostaeva1,2, K.V. Lamonova3, S.M. Orel3, and Yu.G. Pashkevich3
1Institute for Metal Physics, Kyiv 03142, Ukraine
2Donetsk National University, Vinnytsia 21021, Ukraine
3Donetsk Institute for Physics and Engineering, Kyiv 03028, Ukraine
Received June 20, 2017, revised Jule 19, 2017
We report a detailed study of the single-ion magnetic anisotropy of the rare-earth ions in the RFeAsO (R = Сe, Nd, Sm). Energy levels and g-factor values, temperature dependences of magnetic susceptibility components and fourth-order anisotropy constant were calculated by modified crystal field approach. A method for determining the single-ion easy direction has been proposed. It was shown, that the Се3+ and Nd3+ ions easy directions in orthorhombic phase are  and , correspondently. In tetragonal phase the easy direction is  for the both ions. In the case of the Sm3+ ion the easy direction is  irrespectively to the phase symmetry.
PACS: 75.30.Gw Magnetic anisotropy;
Key words: rare-earth oxypnictides, modified crystal field theory, single-ion magnetic anisotropy.
Published online: November 28, 2017