Iron-vacancy superstructure and possible room temperature antiferromagnetic order in superconducting CsyFe2-xSe2

V. Yu. Pomjakushin , D. V. Sheptyakov , E. V. Pomjakushina , Anna Krztoń-Maziopa , K. Conder , D. Chernyshov , V. Svitlyk , Z. Shermadini


Neutron and x-ray powder and single crystal synchrotron diffraction of CsyFe2−xSe2 show the presence of superstructure reflections with propagation vector k=[25,15,1] with respect to the average crystal structure I4/mmm (a~4,c~15 Å). The propagation vector star corresponds to the 5 times bigger unit cell given by transformation A=2a+b, B=−a+2b, C=c. A solution for the atomic structure is found in the space group I4/m with an ordered pattern of iron vacancies corresponding to the iron deficiency x=0.29 and Cs stoichiometry y=0.83. The superstructure satellites are more pronounced in the neutron diffraction patterns suggesting that they can have some magnetic contribution. We have sorted out all possible symmetry adapted magnetic configurations and found that the presence of antiferromagnetic ordering with the ordered magnetic moment of Fe with ≃2μB does not contradict the experimental data. However, the solutions space is highly degenerate and we cannot choose a specific solution. Instead we propose possible magnetic configurations with the Fe magnetic moments in (ab) plane or along c axis. The superstructure is destroyed above Ts≃500 K by a first-order-like transition.
Author V. Yu. Pomjakushin - [Paul Scherrer Institut]
V. Yu. Pomjakushin,,
, D. V. Sheptyakov - [Paul Scherrer Institut]
D. V. Sheptyakov,,
, E. V. Pomjakushina - [Paul Scherrer Institut]
E. V. Pomjakushina,,
, Anna Krztoń-Maziopa (FC / CICSST)
Anna Krztoń-Maziopa,,
- Chair Of Inorganic Chemistry And Solid State Technology
, K. Conder - [Paul Scherrer Institut]
K. Conder,,
, D. Chernyshov - [European Synchrotron Radiation Facility]
D. Chernyshov,,
, V. Svitlyk - [European Synchrotron Radiation Facility]
V. Svitlyk,,
, Z. Shermadini - [Paul Scherrer Institut]
Z. Shermadini,,
Journal seriesPhysical Review B, ISSN 1098-0121, (A 35 pkt)
Issue year2011
ASJC Classification3104 Condensed Matter Physics; 2504 Electronic, Optical and Magnetic Materials
Languageen angielski
Iron vacancy superstructure and possible AFM order in CsyFe2-xSe2- PhysRevB 83 -2011.pdf 436.23 KB
Score (nominal)35
Publication indicators WoS Citations = 74; Scopus Citations = 81; Scopus SNIP (Source Normalised Impact per Paper): 2011 = 1.423; WoS Impact Factor: 2011 = 3.691 (2) - 2011=3.405 (5)
Citation count*92 (2015-11-27)
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