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

Abstract

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 respect to the average crystal structure I4/mmm (a = 4, c = 15A). 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 groups P42/n and 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 possible symmetry adapted magnetic configurations and found that the presence of AFM ordering with the ordered magnetic moment of Fe with 2μB does not contradict to 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.

5 pages, 5 figures, 3 tables, Submitted to Phys Rev B, no change in manuscript. Fixed references to be automatically recognized by arxive system

References in corpus (4)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 32 K in single crystal Rb${}_{0.78}$Fe${}_2$Se${}_{1.78}$}
• Synthesis and crystal growth of Cs0.8(FeSe0.98)2: a new iron-based superconductor with Tc=27K
• Coexistence of Magnetism and Superconductivity in the Iron-based Compound Cs_0.8(FeSe_0.98)_2

Cited by in corpus (55)

• The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
• Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor
• Nanoscale phase separation in the iron chalcogenide superconductor K0.8Fe1.6Se2 as seen via scanning nanofocused x-ray diffraction
• Common Crystalline and Magnetic Structure of superconducting A2Fe4Se5
• Intrinsic phase separation in superconducting K0.8Fe1.6Se2 (Tc= 31.8 K) single crystals
• Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizations
• Coexistence of superconductivity and antiferromagnetism in single crystals $A_{0.8}F{e}_{2-y}S{e}_2$ (A= K, Rb, Cs, Tl/K and Tl/Rb): evidence from magnetization and resistivity
• KFe_2Se_2 is the parent compound of K-doped iron selenide superconductors
• Nanoscale phase separation of antiferromagnetic order and superconductivity in K${}_{0.75}$Fe${}_{1.75}$Se${}_2$
• Magnetic Resonant Mode in the Low-Energy Spin-Excitation Spectrum of Superconducting Rb2Fe4Se5 Single Crystals
• Spin Waves and magnetic exchange interactions in insulating Rb${}_{0.89}$Fe${}_{1.58}$Se${}_2$
• Phase Diagram of KxFe2-ySe2-zSz and the Suppression of its Superconducting State by an Fe2-Se/S Tetrahedron Distortion
• New ternary ThCr2Si2-type iron-selenide superconducting materials: synthesis, properties and simulations
• Superconductivity in the iron selenide KxFe2Se2 (0 <= x <= 1)
• Reciprocal-space structure and dispersion of the magnetic resonant mode in the superconducting phase of Rb(x)Fe(2-y)Se2 single crystals
• The intercalation chemistry of layered iron chalcogenide superconductors
• Superconducting properties of single-crystalline A_{x}Fe_{2-y}Se_{2} (A=Rb, K) studied using muon spin spectroscopy
• Anisotropic magnetism, superconductivity, and the phase diagram of Rb(1-x)Fe(2-y)Se2
• Antiferromagnetic order and superlattice structure in nonsuperconducting and superconducting RbyFe(1.6+x)Se2
• Infrared spectrum and its implications for the electronic structure of the semiconducting iron selenide K${}_{0.83}$Fe${}_{1.53}$Se${}_2$
• Microstructural analysis of phase separation in iron chalcogenide superconductors
• Imaging the coexistence of superconductivity and a charge density modulation in K0.73Fe1.67Se2 superconductor
• Synthesis, crystal and magnetic structure of iron selenide BaFe2Se3 with possible superconductivity at Tc=11K
• Conformity of spin fluctuations in alkali-metal iron selenide superconductors inferred from the observation of a magnetic resonant mode in K(x)Fe(2-y)Se(2)
• The preparation and phase diagrams of (${}^7$Li${}_{1-x}$Fe${}_x$OD)FeSe and (Li${}_{1-x}$Fe${}_x$OH)FeSe superconductors
• Structural, Magnetic and Electronic Properties of the Iron-Chalcogenide A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Cs, Rb, Tl and etc.) Superconductors
• Structure and composition of the superconducting phase in alkali iron selenide K${}_y$Fe${}_{1.6+x}$Se${}_2$
• Intrinsic crystal phase separation in antiferromagnetic superconductor RbyFe2-xSe2: a diffraction study
• Spin-wave excitations and superconducting resonant mode in Cs(x)Fe(2-y)Se2
• Spin reorientation in TlFe1.6Se2 with complete vacancy ordering
• Interplay between Superconductivity and Magnetism in Rb0.8Fe1.6Se2 under Pressure
• Coexistence of different electronic phases in the K0.8Fe1.6Se2 superconductor: a bulk-sensitive hard x-rays spectroscopy study
• Two-magnon Raman scattering in A${}_{0.8}$Fe${}_{1.6}$Se${}_2$ systems: competition between superconductivity and antiferromagnetic order
• "Cigar" Fermi surface as a possible requisite for superconductivity in iron-based superconductors
• Modulated superconductivity due to vacancy and magnetic order in $A_x$Fe${}_{2-x/2}$Se${}_2$ [$A=$Cs, K, (Tl,Rb), (Tl,K)] iron-selenide superconductors
• Uniform Patterns of Fe Vacancy Ordering in the Kx(Fe,Co)2-ySe2 Superconductors
• Temperature and pressure evolution of the crystal structure of Ax(Fe1-ySe)2 (A = Cs, Rb, K) studied by synchrotron powder diffraction
• Magnetic Frustration and Iron-Vacancy Ordering in Iron-Chalcogenide
• Large local disorder in the superconducting K_{0.8}Fe_{1.6}Se_{2} studied by extended x-ray absorption fine structure
• (PI,0) antiferromagnetic spin excitations in superconducting Rb0.82Fe1.68Se2
• Superconductivity mediated by the antiferromagnetic spin-wave in chalcogenide iron-base superconductors
• Phase co-existence and structured diffuse scattering seen by X-ray 3D mapping of reciprocal space for Cs0.8Fe1.6Se2
• SDW transition of Fe1 zigzag chains and metamagnetic transition of Fe2 in TaFe${}_{1+y}$Te${}_3$
• Electronic and Magnetic Structures of Chain Structured Iron Selenide Compounds
• Evolution of superconductivity in isovalent Te-substituted KxFe2-ySe2 crystals
• Compressibility and pressure-induced disorder in superconducting phase-separated Cs0.72Fe1.57Se2
• Two-dimensional Cs-vacancy superstructure in iron-based superconductor $C{s}_{0.8}F{e}_{1.6}S{e}_2$
• The Superconducting Transition Temperatures of Fe1+xSe1--y, Fe1+xSe1--yTey and (K/Rb/Cs)zFe2--xSe2
• Spin excitations in K${}_{0.84}$Fe${}_{1.99}$Se${}_2$ superconductor as studied by Mössbauer spectroscopy
• Structure, superconductivity, and magnetism in Rb1-xFe1.6Se2-zSz
• Connection between ambient-pressure and pressure-induced superconducting phases in alkaline iron selenide superconductors
• Impurity effects on spin dynamics in magnetic and superconducting iron pnictides and chalcogenides
• Fermi surface evolution and checker-board block-spin antiferromagnetism in $A_x$Fe${}_{2-y}$Se${}_2$
• Synthesis and physical properties of the new potassium iron selenide superconductor K0.80Fe1.76Se2
• Formation of single-phase disordered CsxFe2-ySe2 at high pressure