A Powder Neutron Diffraction Study of the Magnetic Structure of FeV2S4

Variable-temperature powder neutron diffraction data demonstrate that FeV2S4undergoes a transition to a long-range magnetically ordered state at 135(7) K, in agreement with magnetic susceptibility data. High-resolution neutron diffraction data collected at 1.9 K reveal that magnetic ordering results in a doubling of the crystallographic unit-cell dimensions (I2/m a=5.8302 (2),b=3.2761(1),c=11.2398(4) ?,BETA=92.046(2)°) in theaandcdirections and that the magnetic structure is described by a propagation vector of ( , 0, ). Cations in an ordered defect layer, 76% of which are Fe(II), possess an average ordered moment of 1.86(5)MUB, which is directed at an angle of 75° to the layer. Cation–cation interactions reduce the average moment of cations in theMS2unit to 0.17(4)MUB. The complex magnetic structure involves essentially collinear antiferromagnetic ordering between nearest-neighbor cations.