Iron vacancy superstructure and possible room temperature antiferromagnetic order in superconducting Cs_{y}Fe_{2-x}Se_2

V. Yu. Pomjakushin, D. V. Sheptyakov, E. V. Pomjakushina +5

Neutron and x-ray powder and single crystal synchrotron diffraction of CsyFe2-xSe2 show the presence of superstructure reflections with propagation vector k=[2/5, 1/5, 1] with resp…