Phase formation and superconductivity in REBaSrCu3−x(PO4)xOy (0 ≤ x ≤ 0.3)
15 Jul 1997-Physica C-superconductivity and Its Applications (North-Holland)-Vol. 280, Iss: 4, pp 327-334
TL;DR: Oxy-anion substituted phases of the composition REBaSrCu 2.8 (PO 4 3− ) 0.2 O y have been synthesized as discussed by the authors, and single phase formation is achieved only for the larger rare earths (La → Ho and Y) and all the phases crystallize in the tetragonal 123 structure.
Abstract: Oxy-anion (PO 4 3− ) substituted phases of the composition REBaSrCu 2.8 (PO 4 ) 0.2 O y have been synthesized. Single phase formation is achieved only for the larger rare earths (La → Ho and Y) and all the phases crystallize in the tetragonal 123 structure. IR studies confirm the presence of a phosphate group in the structure. The total oxygen content (including that associated with the oxy-anion PO 4 3− ) has been found to be in the range 7.01 to 7.10 per formula unit. Except for RE = La, Nd, Yb and Lu, all the phases exhibit superconductivity and the T c,zero values vary from 18 to 38 K. The T c,zero increases with decreasing size of RE 3+ . ErBaSrCu 3 O 7 is multiphasic and single phase formation is achieved for the first time by phosphate substitution at the copper site. Single phase formation is encountered for x = 0.10 and 0.15 with T c,zero values of 54 and 37 K respectively.
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01 Jan 1978TL;DR: In this article, the normal modes of vibration are illustrated and corresponding vibrational frequencies are listed for each type, including diatomic, triatomic, fouratomic, five-atomic, six-atomic and seven-atomic types.
Abstract: Inorganic molecules (ions) and ligands are classified into diatomic, triatomic, four-atomic, five-atomic, six-atomic, and seven-atomic types, and their normal modes of vibration are illustrated and the corresponding vibrational frequencies are listed for each type. Molecules of other types are grouped into compounds of boron, carbon, silicon, nitrogen, phosphorus, and sulfur, and the structures and infrared (IR)/Raman spectra of select examples are shown for each group. Group frequency charts including band assignments are shown for phosphorus and sulfur compounds. Other group frequency charts include hydrogen stretching frequencies, halogen stretching frequencies, oxygen stretching and bending frequencies, inorganic ions, and metal complexes containing simple coordinating ligands.
Keywords:
inorganic compounds;
coordination compounds;
diatomic molecules (ligands);
triatomic molecules (ligands);
four-atomic molecules (ligands);
five-atomic molecules (ligands);
six-atomic molecules (ligands);
seven-atomic molecules (ligands);
boron compounds;
carbon compounds;
silicon compounds;
nitrogen compounds;
phosphorus compounds;
sulfur compounds;
group frequency charts
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TL;DR: In this article, the authors investigated the composition YSr2Cu3-xMxOy and obtained the 123-structure for M= Li, Al, Ti, V, Cr, Fe, Co, Ga, Ge, Mo, W and Re.
Abstract: We have investigated the composition YSr2Cu3-xMxOy and obtained the 123-structure for M= Li, Al, Ti, V, Cr, Fe, Co, Ga, Ge, Mo, W and Re. Superconductivity is observed for the compounds with M=Ti, V, Fe, Co, Ga, Ge, Mo, W and Re at low levels of substitution context x. The highest Tzeroc is 73 K for the compound YSr2Cu2.85Re0.15O7.12. Tcs are enhanced by decreasing x or increasing y, which draw the rise of hole concentration pave (Cu2+p). Except for the compounds with M=V and Cr, the structures are tetragonal, while those of the compounds YSr2Cu3-xCrxOy are orthorhombic, and YSr2Cu3-x VxOy shows the structural transition from tetragonal to orthorhombic by HIP treatment with the simultaneous transition from superconductivity to metallic transport property. This Sr-based 123-structure is stabilized by doping elements with ionic radii=0.35-0.49 A or 0.525-0.62 A supposing 4- or 6-coordination, respectively, except for M=Li.
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TL;DR: The possibility of synthesizing phases of general composition YSr 2 Cu 3− x M x O 7± y has been examined for a wide variety of metals M.
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TL;DR: The crystal structure of a new compound, (C0.4Cu0.6)Sr2(Y0.86Sr0.14)Cu2O7, is derived from the structure of YBa2Cu3O7.
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92 citations