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SYNTHESIS AND NEUTRON POWDER DIFFRACTION STUDY OF THE SUPERCONDUCTOR HGBA2CACU2O6+DELTA BEFORE AND AFTER HEAT-TREATMENTстатья
Информация о цитировании статьи получена из
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Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 9 ноября 2013 г.
- Авторы: ANTIPOV EV, CAPPONI JJ, CHAILLOUT C., CHMAISSEM O., LOUREIRO SM, MAREZIO M., PUTILIN SN, SANTORO A., THOLENCE JL
- Журнал: Physica C: Superconductivity and its Applications
- Том: 218
- Номер: 3-4
- Год издания: 1993
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 348
- Последняя страница: 355
- DOI: 10.1016/0921-4534(93)90035-O
- Аннотация: The crystal structure of the superconductor HgBa2CaCu2O6+delta has been analyzed by neutron powder diffraction techniques at room temperature and at 10 K. The compound crystallizes with the symmetry of space group P4/mmm and lattice parameters a = 3.8526(2), c = 12.6367(8) angstrom. The structure is made of the sequence of layers ...[(BaO)(CuO2)(Ca)(CuO2)(BaO)(HgO(delta))]... The compound, prepared by a solid-state reaction between HgO and the precursor Ba2CaCu2Ox at 18 kbar and 880-degrees-C, has an oxygen content corresponding to delta = 0.35(2) and a transition temperature of T(c) congruent-to 104 K. Annealing in O2 (300-degrees-C for 20 h) reduces the oxygen content to delta = 0.28(2). A sample annealed under the same conditions or in N2 (250-degrees-C for 12 h) was found to have a T(c) of 123 K. Additional annealing in N2 at 400-degrees-C for 18 h lowers T(c) to 110 K. Our results indicate that the material with delta = 0.35 is overdoped. The oxygen above the O6 stoichiometry is located on the Hg layers of the structure, at the positions 1/2, 1/2, 0. No evidence has been found of the substitution of mercury by copper. The copper and oxygen atoms of the (CuO2) layers are almost exactly coplanar in this compound.
- Добавил в систему: Антипов Евгений Викторович