Control of the superconducting properties of Sr{sub 2−x}Ca{sub x}VO{sub 3}FeAs through isovalent substitution

Journal Article · Fri Aug 15 00:00:00 EDT 2014 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2014.02.024· OSTI ID:22443376

Corkett, Alex J.; Free, David G. ^[1]; Cassidy, Simon J. ^[1]; Ramos, Silvia ^[2]

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1. Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR (United Kingdom)
2. 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

Related Subjects

37 INORGANIC
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