Intracluster interactions in “butterfly” {Fe(3)LnO(2)} molecules.

The magnetization contributions of the Fe-3 and Ln subcluster in the “butterfly” molecule [Fe(3)Ln mu(3)-0)(2)(CCl3COO)8(H2O)(THF)(3)], in brief {Fe(3)LnO(2)], with Ln=Lu, Gd, Tb, Dy and Ho, have been determined by a combination of vibrating sample magnetometry and x-ray circular magnetic dichroism at low temperature and magnetic field up to 14 T. These contributions have been explained in terms of an effective spin model where the Fe3 is described by a S-Fe3 = 5/2 spin, Gd by an isotropic J=7/2, Dy by a Kramers doublet, and non-Kramers ions Tb and Ho by a ligand field split doublet. The intracluster interactions J(FeLn) have been found to amount to a few K. (C) 2015 Elsevier B.V. All rights reserved.