Simultaneous Antiferromagnetic Fe3+ and Nd3+ Ordering in NdFe3(11BO3)4
  By means of magnetic susceptibility and specific heat measurements, x-ray and unpolarised neutron diffraction investigations on powder and single-crystal samples, simultaneous long-range antiferromagnetic Fe and Nd ordering in NdFe3(11BO3)4 with R 3 2 chemical structure has been found at temperatures below TN = 30.5(5) K down to 1.6 K. At temperatures down to 20 K to the propagation vector is khex = [0,0,3/2] and becomes slightly incommensurate at lower temperatures. Symmetry analysis yields magnetic spiral configurations with the magnetic moments oriented parallel to hexagonal basal plane according to the irreducible representations tau_3 in the commensurate case. This is in agreement with the easy directions of magnetisation perpendicular to the c-axis as determined by magnetic susceptibility measurements. At 1.6 K the magnetic Fe moment amounts to 4.9 muB close to the free ion moment of Fe3+. The magnetic Nd3+ moment saturates presumably due to crystal-field effects at 2.7 muB. 
P. Fischer, V. Pomjakushin, D. Sheptyakov, L. Keller, M. Janoschek, B.   Roessli, J. Schefer, G. Petrakovskii, L. Bezmaterni...