Superconductivity and crystal structure of Ln2Ba4Cu7O14+δ (Ln=Er, Y, Ho, Dy, Nd)
| Autor: | P.C. Lanchester, R. Walia, D.B. Currie, Mark T. Weller |
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| Rok vydání: | 1994 |
| Předmět: |
Lanthanide
Materials science Transition temperature Neutron diffraction Analytical chemistry Energy Engineering and Power Technology chemistry.chemical_element Crystal structure Condensed Matter Physics Oxygen Copper Magnetic susceptibility Electronic Optical and Magnetic Materials chemistry Electrical and Electronic Engineering Stoichiometry |
| Zdroj: | Physica C: Superconductivity. 224:43-50 |
| ISSN: | 0921-4534 |
| DOI: | 10.1016/0921-4534(94)90603-3 |
| Popis: | The crystal structure of Ln 2 Ba 4 Cu 7 O 14+δ (Ln=Y, lanthanide) is derived from alternate blocks of the LnBa 2 Cu 3 O 7- x (123) and LnBa 2 Cu 4 O 8 (124) structures thus incorporating structural regions of oxygen non-stoichiometry and fixed stoichiometry, respectively. Samples containing a range of different lanthanide sizes and varying oxygen contents have been prepared by a high oxygen pressure method; seven have been examined using very high resolution powder neutron diffraction (PND); all have been examined using powder X-ray diffraction (XRD). AC susceptibility measurements indicate that removal of oxygen from the structure can result in either enhancement or reduction of T c , depending on the initial oxygen content of the as-prepared material. The variations in T c , changes in the detailed structure, oxygen content, and non-stoichiometry of the single chain copper site are discussed. |
| Databáze: | OpenAIRE |
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