Microstructural analysis of phase separation in iron chalcogenide superconductors

Abstract

The interplay between superconductivity, magnetism and crystal structure in iron-based superconductors is a topic of great interest amongst the condensed matter physics community as it is thought to be the key to understanding the mechanisms responsible for high temperature superconductivity. Alkali metal doped iron chalcogenide superconductors exhibit several unique characteristics which are not found in other iron-based superconducting materials such as antiferromagnetic ordering at room temperature, the presence of ordered iron vacancies and high resistivity normal state properties. Detailed microstructural analysis is essential in order to understand the origin of these unusual properties. Here we have used a range of complementary scanning electron microscope based techniques, including high-resolution electron backscatter di raction mapping, to assess local variations in composition and lattice parameter with high precision and sub-micron spatial resolution. Phase separation is observed in the Csx Fe2-ySe2 crystals, with the minor phase distributed in a plate-like morphology throughout the crystal. Our results are consistent with superconductivity occurring only in the minority phase.

Accepted for publication in a special edition of Supercond. Sci. Technol

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Cited by in corpus (15)

• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Influence of microstructure on superconductivity in K${}_x$Fe${}_{2-y}$Se${}_2$ and evidence for a new parent phase K${}_2$Fe${}_7$Se${}_8$
• Evolution of precipitate morphology during heat treatment and its implications for the superconductivity in KxFe1.6+ySe2 single crystals
• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Structure and composition of the superconducting phase in alkali iron selenide K${}_y$Fe${}_{1.6+x}$Se${}_2$
• Spin-wave excitations and superconducting resonant mode in Cs(x)Fe(2-y)Se2
• Superconductivity and magnetism in RbxFe2-ySe2: Impact of thermal treatment on mesoscopic phase separation
• Spin resonance in the superconducting state of Li${}_{1-x}$Fe${}_x$ODFe${}_{1-y}$Se observed by neutron spectroscopy
• High resolution characterisation of microstructural evolution in Rb${}_x$Fe${}_{2-y}$Se${}_2$ crystals on annealing
• Effective medium approximation and the complex optical properties of the inhomogeneous superconductor K_{0.8}Fe_{2-y}Se_2
• Interplay of the electronic and lattice degrees of freedom in A_{1-x}Fe_{2-y}Se_{2} superconductors under pressure
• Two-dimensional Cs-vacancy superstructure in iron-based superconductor $C{s}_{0.8}F{e}_{1.6}S{e}_2$
• Structural disorder in Li(x)[C5H5N](y)Fe(2-z)Se2 and Cs(x)Fe(2-z)Se2 superconductors studied by Mössbauer spectroscopy
• Low-temperature-compatible tunneling-current-assisted scanning microwave microscope utilizing a rigid coaxial resonator
• Phase separation in iron chalcogenide superconductor Rb0.8+xFe1.6+ySe2 as seen by Raman light scattering and band structure calculations