Control of the superconducting properties of Sr{sub 2−x}Ca{sub x}VO{sub 3}FeAs through isovalent substitution
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR (United Kingdom)
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom)
The effect of the isovalent substitution of Sr{sup 2+} by Ca{sup 2+} on the structure and superconducting properties of Sr{sub 2−x}Ca{sub x}VO{sub 3}FeAs is described in the compositional range 0≤x≤0.5. SQUID magnetometry measurements reveal that after an initial increase in T{sub c}, which is maximised at 29.5 K in Sr{sub 1.95}Ca{sub 0.05}VO{sub 3}FeAs, a rapid suppression of superconductivity is observed with increasing x. XANES spectra of Sr{sub 2−x}Ca{sub x}VO{sub 3}FeAs collected on the Fe and V absorption K-edges show that the position of both edges are invariant with composition within the experimental uncertainty. A combination of synchrotron X-ray powder diffraction and neutron powder diffraction techniques is used to rationalise the observed changes in T{sub c} with x, in terms of changes to the structure of the FeAs layer upon partial Ca substitution. These findings demonstrate that superconductivity in the Fe-based superconductors is extremely sensitive to the crystal structure with T{sub c} maximised in samples with regular FeAs{sub 4}-tetrahedra. - Graphical abstract: Superconducting transition temperature is controlled by structural parameters in Sr{sub 2−x}Ca{sub x}VO{sub 3}FeAs. - Highlights: • Substitution of Sr by Ca in the superconductor Sr{sub 2}VO{sub 3}FeAs is isovalent. • Relationship between superconducting T{sub c} and structural parameters is demonstrated. • Linear dependence of T{sub c} on structural parameters rather than composition.
- OSTI ID:
- 22443376
- Journal Information:
- Journal of Solid State Chemistry, Vol. 216; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ABSORPTION SPECTROSCOPY
CALCIUM IONS
CONTROL
CRYSTAL STRUCTURE
IRON ARSENIDES
LAYERS
NEUTRON DIFFRACTION
SPECTRA
SQUID DEVICES
STRONTIUM IONS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY