Eight new high-temperature superconductors with the 1:2:4 structure

Morris, Donald E.; Nickel, Janice H.; Wei, J.Y.T.; Asmar, N. G.; Scott, Jeffrey S.; Scheven, Ulrich M.; Hultgren, C. T.; Markelz, Andrea; Post, Jeffrey E.; Heaney, Peter J.; Veblen, David R.; Hazen, Robert M.

doi:10.1103/physrevb.39.7347

Cited by 263 publications

(14 citation statements)

References 24 publications

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“…(These behaviors may occur because double Cu-O chains are compressed with decrease of c-axis parameter.) The both relationships correspond to the reported ones of Morris et al 9 and Adachi et al 10 . Fig.3.…”

Section: Results and Discussion 31 Substitution Of Rare Earth Elementsupporting

confidence: 92%

Synthesis of superconductor REBa2Cu4O8 phase by molten hydroxide method

Nagira

Hara

Yamada

et al. 2010

Trans. Mat. Res. Soc. Japan

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Superconducting oxide REBa 2 Cu 4 O 8 (RE124; RE=Y, Sm, Eu, Gd, Dy, Ho, Er, Tm and Yb) were synthesized by a molten hydroxide method under an ambient pressure. Rare earth oxide, barium carbonate and copper oxide powder were used as starting materials and potassium hydroxide (KOH) was used as a solvent material. The synthesis was carried out by a heating treatment at 715°C. XRD peaks of RE124 using small ionic radius elements such as Y and Dy-Yb were obtained to be intense and sharp. The effect of RE substitution in superconductivity and lattice constant was investigated by SQUID and XRD. Superconducting critical temperature (Tc) increased and c-axis length decreased as the ion radius decreased. In order to investigate relationship between heating temperature and synthesized phases, Y124 were prepared at different heating temperature from 500˚C to 800˚C. Y124 phase appeared in the rage between 600˚C and 800˚C, and the most intense at 700˚C. No Y124 phase was observed at 500˚C. From these results, it was considered that small ion radius elements such as Y and Dy-Yb are appropriate to easily synthesize RE124 by this method, and the optimal heating temperature is about 700˚C.

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Section: Results and Discussion 31 Substitution Of Rare Earth Elementsupporting

confidence: 92%

Synthesis of superconductor REBa2Cu4O8 phase by molten hydroxide method

Nagira

Hara

Yamada

et al. 2010

Trans. Mat. Res. Soc. Japan

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“…Oxygen vacancies might cause phonon-point-defect scattering in both Y123 and Y124 but this seems less likely for Y124 because the oxygen content is essentially stoichiometric. 5,6 In fact, Fig. 4 shows evidence that phonon-point-defect scattering is also not very important in well oxygenated Y123.…”

Section: Discussionmentioning

confidence: 92%

“…[2][3][4] It was later shown [5][6][7] that the compound is stable over a wide range of temperature and oxygen pressures. Essentially phase-pure research samples have been synthesized in high-pressure oxygen at temperatures above 1000°C and the results of many physical property studies have been published.…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
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The thermal conductivity and electrical resistivity were measured on two samples of the cuprate superconductor YBa 2 Cu 4 O 8 ͑Y124͒. The results pass through a maximum at about half of the superconducting transition temperature T c . The peak value is much higher than the peak value for polycrystalline YBa 2 Cu 3 O 7Ϫ␦ , Y123, and is about equal to ab plane values for good melt processed Y123. In the normal state most of the is due to phonon transport p and estimates of p were obtained from the data by making a correction for electronic transport. Phonon-phonon and phonon-electron scattering limit the p of both Y124 and Y123. In the two compounds, the phonon-phonon scattering is about equally strong, but electron-phonon scattering is considerably weaker in Y124. In the superconducting state, below the maximum at T c /2, varies as T n (nϷ1/2). This behavior has also been observed in Y123, but is not consistent with phonon scattering theory. The implications of this observation are discussed. ͓S0163-1829͑98͒08117-X͔ THERMAL CONDUCTIVITY OF POLYCRYSTALLINE . . .

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“…Electron conduction occurs by hopping between octahedral Fe2+ and Fe3+ sites. Substantial nonstoichiometry can be induced in magnetite via oxidation according to: 8/3Fe2+ + 2/3O2(g) «• 4 / 3 0 o = + 8/3Fe3+ + VFe (4) Nevertheless, since both Fe2+ and Fe3+ are present in large and nearly equal amounts, their concentrations vary only slightly with the defect concentration. Conductivity, which is determined by the product of octahedral Fe2+ and Fe3+, and Seebeck coefficient, which is determined by the ratio of octahedral Fe3+ and Fe2+, are both essentially oxygen partial pressure independent until very large concentrations of defects are generated.…”

Section: Discussionmentioning

confidence: 99%

Characterization of YBa₂Cu₄O₈ high temperature electrical properties and thermodynamic stability

Hong

Mason

1991

J. Mater. Res.

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Via in situ electrical property measurements (conductivity, Seebeck coefficient) over the temperature range 500-800 °C and oxygen partial pressure range 1 0~4 -l atm, the equilibrium transport properties and stability range of YBa2Cu4O8 were determined. YBa2Cu408 behaves like the intrinsically mixed-valent compound, magnetite (Fe3O4), with small variations in electrical properties with changes in oxygen partial pressure. The decomposition boundary to YBa2Cu306+j/ (or YBa2Cu3.5O7.5±z) and CuO occurs at Iog(po2,atm) = -1.24 x 104/T(K) + 11.01(773 < T(K) ^ 1073).

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Eight new high-temperature superconductors with the 1:2:4 structure

Cited by 263 publications

References 24 publications

Synthesis of superconductor REBa<sub>2</sub>Cu<sub>4</sub>O<sub>8</sub> phase by molten hydroxide method

Synthesis of superconductor REBa<sub>2</sub>Cu<sub>4</sub>O<sub>8</sub> phase by molten hydroxide method

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Characterization of YBa₂Cu₄O₈ high temperature electrical properties and thermodynamic stability

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Eight new high-temperature superconductors with the 1:2:4 structure

Cited by 263 publications

References 24 publications

Synthesis of superconductor REBa<sub>2</sub>Cu<sub>4</sub>O<sub>8</sub> phase by molten hydroxide method

Synthesis of superconductor REBa<sub>2</sub>Cu<sub>4</sub>O<sub>8</sub> phase by molten hydroxide method

Thermal conductivity of polycrystallineYBa2Cu4O8Williams1, Scarbrough2, Schmitz3 et al. 1998Phys. Rev. B10050View full textAdd to dashboardCite

Characterization of YBa2Cu4O8 high temperature electrical properties and thermodynamic stability

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Product

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About

Thermal conductivity of polycrystallineYBa2Cu4O8
Williams
¹
,
Scarbrough
²
,
Schmitz
³

et al. 1998
Phys. Rev. B
10
0
5
0
View full text Add to dashboard Cite

Characterization of YBa₂Cu₄O₈ high temperature electrical properties and thermodynamic stability