Journal of Superconductivity and Novel Magnetism

, Volume 27, Issue 4, pp 1003–1007 | Cite as

Temperature Dependence of \(\sqrt{2} \times \sqrt{2}\) Phase in Superconducting K0.8Fe1.6Se2 Single Crystal

  • A. Ricci
  • B. Joseph
  • N. Poccia
  • G. Campi
  • N. L. Saini
  • A. Bianconi
Original Paper


We report the structural phase transition properties of the newly discovered K0.8Fe1.6Se2 superconductor (T c =31.8 K) using synchrotron single-crystal X-ray diffraction. The basic structure of the sample at room temperature is found to be tetragonal ThCr2Si2-type, modulated by a vacancy ordering induced superlattice structure together with a coexisting minority phase having a \(\sqrt{2} \times \sqrt{2}\) ordering. At 520 K, the reflections corresponding to the \(\sqrt{2} \times \sqrt{2}\) phase merge with the parent tetragonal phase. The superlattice peaks corresponding to the vacancy ordering disappear at 580 K, indicating an order-disorder phase transition at this temperature.


Iron-chalcogenides Nanoscale phase separation Superconductivity complex materials 


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • A. Ricci
    • 1
  • B. Joseph
    • 2
    • 3
  • N. Poccia
    • 4
  • G. Campi
    • 5
  • N. L. Saini
    • 2
  • A. Bianconi
    • 3
  1. 1.Deutsches Elektronen-Synchrotron DESYHamburgGermany
  2. 2.Department of PhysicsSapienza University of RomeRomeItaly
  3. 3.Rome International Center of Materials Science, Superstripes (RICMASS)RomaItaly
  4. 4.MESA+ Institute for NanotechnologyUniversity of TwenteEnschedeNetherlands
  5. 5.Institute of CrystallographyCNRRomaItaly

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