Homologous series of copper-oxide superconductors: Synthesis of members up to

Gao, Weibo; Oishi, Keiichiro; Suematsu, Hisayuki; Yamauchi, H.; Karppinen, Maarit

doi:10.1016/j.ssc.2011.06.010

Cited by 4 publications

(7 citation statements)

References 19 publications

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“…In this category, the number of CuO 2 planes is fixed at two, and the fluorite block functions as a spacer between them. A wide range of thicknesses have been reported, up to s = 6 [40]. Commonly, the base fluorite layer oxide is CeO 2 or YO 2 , but significant substitution with other lanthanoids (up to 67%) is possible [41][42][43][44][45].…”

Section: Figurementioning

confidence: 99%

“…At high temperatures (usually 700-1200 • C), a solid-state rearrangement of atoms is mediated by enhanced diffusion. Variants of the solid-state method are the nitrate route [40,51,67] and sol-gel route [30,32,68], in which the primary precursors are initially mixed by dissolution, followed by drying and annealing with intermediate grinding.…”

mentioning

confidence: 99%

“…At high temperatures (usually 700-1200 °C), a solid-state rearrangement of atoms is mediated by enhanced diffusion. Variants of the solid-state method are the nitrate route [40,51,67] and sol-gel route [30,32,68], in which the primary precursors are initially mixed by dissolution, followed by drying and annealing with intermediate grinding. Low-pressure oxygenation (LPO) methods are taken to include the use of O2 atmosphere under ambient pressure synthesis [45,58,69,70], but also pressurized treatments in gas phase, e.g., in an autoclave [23,47,52,54,56] at pressures up to ca.…”

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confidence: 99%

“…External oxidizers are added to the HPO step as solids that release oxygen at high temperatures and leave behind a residue after the HPO treatment. The most common external oxidizers are Ag 2 O 2 and KClO 3 , and occasionally KClO 4 [40,50,52], that result in Ag or KCl residues, respectively. KCl can be washed away, at the expense of risking sample degradation, while Ag residues are practically inseparable from the cuprate product.…”

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confidence: 99%

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Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

et al. 2021

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Within the cuprate constellation, one fixed star has been the superconducting dome in the quantum phase diagram of transition temperature vs. the excess charge on the Cu in the CuO2-planes, p, resulting from O-doping or cation substitution. However, a more extensive search of the literature shows that the loss of the superconductivity in favor of a normal Fermi liquid on the overdoped side should not be assumed. Many experimental results from cuprates prepared by high-pressure oxygenation show Tc converging to a fixed value or continuing to slowly increase past the upper limit of the dome of p = 0.26–0.27, up to the maximum amounts of excess oxygen corresponding to p values of 0.3 to > 0.6. These reports have been met with disinterest or disregard. Our review shows that dome-breaking trends for Tc are, in fact, the result of careful, accurate experimental work on a large number of compounds. This behavior most likely mandates a revision of the theoretical basis for high-temperature superconductivity. That excess O atoms located in specific, metastable sites in the crystal, attainable only with extreme O chemical activity under HPO conditions, cause such a radical extension of the superconductivity points to a much more substantial role for the lattice in terms of internal chemistry and bonding.

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confidence: 99%

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Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

et al. 2021

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“…During the past eight years the first six members of the homologous series (Cu 0.75 Mo 0.25 )Sr 2 (Ce,Y) s Cu 2 O 5+2s+δ have been successfully synthesized and investigated. [1][2][3][4][5][6] The reported results indicate that the Cu valence is anomalously higher than in the well-known high-T c cuprates such as YBa 2 6 Cu 2 O 17+δ , respectively. There is a substantial difference between the familiar Hg-m2(n-1)n and Tl-m2(n-1)n homologous series and the present (Cu 0.75 Mo 0.25 )-12s2 series.…”

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confidence: 72%

Overdoped cuprates with high-temperature superconducting transitions

Marezio¹,

Chmaissem

Bougerol

et al. 2013

APL Materials

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Evidence for high-Tc cuprate superconductivity is found in a region of the phase diagram where non-superconducting Fermi liquid metals are expected. Cu valences estimated independently from both x-ray absorption near-edge spectroscopy and bond valence sum measurements are >2.3, and are in close agreement with each other for structures in the homologous series (Cu0.75Mo0.25)Sr2(Y,Ce)sCu2O5+2s+δ with s = 1, 2, 3, and 4. The record short apical oxygen distance, at odds with current theory, suggests the possibility of a new pairing mechanism. The possibility that the charge reservoir layers are able to screen long range coulomb interactions and thus enhance Tc is discussed

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Conduction Band Control of Oxyhalides with a Triple-Fluorite Layer for Visible Light Photocatalysis

et al. 2021

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The discovery of building blocks offers new opportunities to develop and control properties of extended solids. Compounds with fluorite-type Bi 2 O 2 blocks host various properties including lead-free ferroelectrics and photocatalysts. In this study, we show that triple-layered Bi 2 MO 4 blocks (M = Bi, La, Y) in Bi 2 MO 4 Cl allow, unlike double-layered Bi 2 O 2 blocks, to extensively control the conduction band. Depending on M, the Bi 2 MO 4 block is truncated by Bi−O bond breaking, resulting in a series of n-zigzag chain structures (n = 1, 2, ∞ for M = Bi, La, Y, respectively). Thus, formed chain structures are responsible for the variation in the conduction band minimum (−0.36 to −0.94 V vs SHE), which is correlated to the presence or absence of mirror symmetry at Bi. Bi 2 YO 4 Cl shows higher photoconductivity than the most efficient Bi 2 O 2 -based photocatalyst with promising visible-light photocatalytic activity for water splitting. This study expands the possibilities of thickening (2D to 3D) and cutting (2D to 1D) fluorite-based blocks toward desired photocatalysis and other functions.

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Homologous series of copper-oxide superconductors: Synthesis of members up to

Cited by 4 publications

References 19 publications

Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

Overdoped cuprates with high-temperature superconducting transitions

Conduction Band Control of Oxyhalides with a Triple-Fluorite Layer for Visible Light Photocatalysis

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