Precision synthesis of infinite-layer (Sr,La)CuO<sub>2</sub>superconductors

Tanaka, Yoshiaki; Karppinen, Maarit; Yamauchi, H.

doi:10.1088/0953-2048/22/6/065004

Cited by 5 publications

(4 citation statements)

References 13 publications

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“…Despite extensive studies of substitutional chemistry on the IL cuprate, − ,− the apical oxygen incorporated IL-type structure was not reported. This in turn reflects the robustness of the divalent state and structural flexibility of the square-planar coordinated iron.…”

Section: Resultsmentioning

confidence: 99%

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

et al. 2016

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The effect of lanthanoid (Ln = Nd, Sm, Ho) substitution on the structural and physical properties of the infinite-layer iron oxide SrFeO was investigated by X-ray diffraction (XRD) at ambient and high pressure, neutron diffraction, and Fe Mössbauer spectroscopy. Ln for Sr substituted samples up to ∼30% were synthesized by topochemical reduction using CaH. While the introduction of the smaller Ln ion reduces the a axis as expected, we found an unusual expansion of the c axis as well as the volume. Rietveld refinements along with pair distribution function analysis revealed the incorporation of oxygen atoms between FeO layers with a charge-compensated composition of (SrLn)FeO, which accounts for the failed electron doping to the FeO layer. The incorporated partial apical oxygen or the pyramidal coordination induces incoherent buckling of the FeO sheet, leading to a significant reduction of the Néel temperature. High-pressure XRD experiments for (SrHo)FeO suggest a possible stabilization of an intermediate spin state in comparison with SrFeO, revealing a certain contribution of the in-plane Fe-O distance to the pressure-induced transition.

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Section: Resultsmentioning

confidence: 99%

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

et al. 2016

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“…Structure: table I of[78]; T C0 , x and x 0 from[79] 21. Structure: table 1 of[80]; x and x 0 from[81] 22. A, d: table I of[83], sample 7; ζ from Table III of[84], site compositions 0.63 Pb; 0.37 Cu, and 0.85 Y; 0.15 Ca 23.…”

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confidence: 99%

Theory of high-T_Csuperconductivity: transition temperature

Harshman

Fiory

Dow

2011

J. Phys.: Condens. Matter

157

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The superconducting transition temperatures of high-T C compounds based on copper, iron, ruthenium and certain organic molecules are discovered to be dependent on bond lengths, ionic valences, and Coulomb coupling between electronic bands in adjacent, spatially separated layers. 1 Optimal transition temperature, denoted as T C0 , is given by the universal expression k B T C0 = e 2  / ℓζ; ℓ is the spacing between interacting charges within the layers, ζ is the distance between interacting layers and  is a universal constant, equal to about twice the reduced electron Compton wavelength (suggesting that Compton scattering plays a role in pairing). Non-optimum compounds in which sample degradation is evident typically exhibit T C < T C0 . For the 31+ optimum compounds tested, the theoretical and experimental T C0 agree statistically to within  1.4 K. The elemental high T C building block comprises two adjacent and spatially separated charge layers; the factor e 2 / ζ arises from Coulomb forces between them. The theoretical charge structure representing a room-temperature superconductor is also presented.

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“…The reason for this is the difficulty to synthesize this compound. Ceramic samples are always made under high pressure (2-3 GPa) [2,3]. To our knowledge, no single crystals have been obtained up to now.…”

Section: Introductionmentioning

confidence: 99%

Superconducting properties, anisotropy and critical currents of SrLaCuO e-doped epitaxial thin films

Jovanović¹,

Li²,

Raffy³

2011

Supercond. Sci. Technol.

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We report a study on the superconducting properties of e-doped Sr0.88La0.12CuO2 (SLCO) thin films. SLCO has an infinite layer structure consisting of CuO2 planes, 3.40 Å apart, separated by Sr, La planes. Highly c-axis oriented thin films, with a critical temperature of 22–23 K, were epitaxially grown by sputtering. Their resistive transition hardly broadens under a perpendicular magnetic field, giving a narrow vortex liquid region. The critical current densities Jc measured magnetically and by transport are in the 105–106 A cm − 2 range at 4.2 K. The dependence of Jc on the orientation θ of the magnetic field, given by transport measurements, shows that, in contrast to highly anisotropic Bi2Sr2CaCu2Oy, there is no two-dimensional (2D) angular scaling: and in parallel magnetic field Jc decreases with increasing fields. We also found an indication of a quasi-oscillatory behaviour of possibly due to the successive entry of rows of vortices. In addition, the temperature dependence of the critical current is rather close to the behaviour derived from the Ginzburg–Landau theory. So, compared to BiSrCaCuO, this model cuprate appears to be much less anisotropic due to well coupled CuO2 planes and presents a more conventional behaviour.

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Precision synthesis of infinite-layer (Sr,La)CuO₂superconductors

Cited by 5 publications

References 13 publications

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

Theory of high-T_Csuperconductivity: transition temperature

Superconducting properties, anisotropy and critical currents of SrLaCuO e-doped epitaxial thin films

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Precision synthesis of infinite-layer (Sr,La)CuO2superconductors

Cited by 5 publications

References 13 publications

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

Impact of Lanthanoid Substitution on the Structural and Physical Properties of an Infinite-Layer Iron Oxide

Theory of high-TCsuperconductivity: transition temperature

Superconducting properties, anisotropy and critical currents of SrLaCuO e-doped epitaxial thin films

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Product

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Precision synthesis of infinite-layer (Sr,La)CuO₂superconductors

Theory of high-T_Csuperconductivity: transition temperature