Anisotropy in BaFe2Se3 single crystals with double chains of FeSe   tetrahedra
  We studied the anisotropy in physical properties of Ba1.00(4)Fe1.9(1)Se3.1(1) single crystals. BaFe2Se3 is a semiconductor below 300 K. Magnetization measurements show that there is a crossover from short-range antiferromagnetic (AFM) correlations at room temperature to a long-range AFM order with TN = 255 K. The anisotropy of magnetization is consistent with the previous neutron results. This crossover is supported by the heat-capacity measurement, where the phase-transition peak is absent at 255 K. The superconducting transition at about 10 K is likely due to the small amount of beta-FeSe impurities. 
Hechang Lei, Hyejin Ryu, Anatoly Frenkel, and C. Petrovic
cond-mat.supr-con cond-mat.mtrl-sci