| Автор | C Changkang |
| Автор | A J S Chowdhury |
| Автор | H Yongle |
| Автор | M Spears |
| Автор | J W Hodby |
| Автор | B M Wanklyn |
| Дата выпуска | 1994-11-01 |
| dc.description | A series of experiments have been carried out on the influence of additives on the crystal growth and superconductivity of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> (YBCO) crystals grown in alumina crucibles from the eutectic self-flux system of BaO-CuO. The single additives were B<sub>2</sub>O<sub>3</sub>, Bi<sub>2</sub>O<sub>3</sub>, BaF<sub>2</sub> or BaCl<sub>2</sub> and the double additives were BaF<sub>2</sub>-B<sub>2</sub>O<sub>3</sub> or BaF<sub>2</sub>-Bi<sub>2</sub>O<sub>3</sub>. It was found that a small amount of BaF<sub>2</sub> greatly improved not only the crystal growth, by increasing solute solubility and crystal yield, but also the superconductivity by reducing Al contamination and resulting in a chemical composition approaching stoichiometry. As a result, single crystals up to 20*10*0.5 or 12*10*1 mm<sup>3</sup> in size have been obtained, and a superconducting transition temperature of 92.5 K with a transition width of 1 K in the as-grown state, or T<sub>c</sub>=93 K with transition width <1 K after annealing in oxygen have been reached by using BaF<sub>2</sub> as additive. A model is proposed to interpret these improvements: it incorporates F<sup>-</sup> induced monomolecular clusters in the high-temperature solution and preferential adsorption of F<sup>-</sup> on the surface of the growing crystal. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Improvement of crystal growth and superconductivity of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> by additive |
| Тип | paper |
| DOI | 10.1088/0953-2048/7/11/003 |
| Electronic ISSN | 1361-6668 |
| Print ISSN | 0953-2048 |
| Журнал | Superconductor Science and Technology |
| Том | 7 |
| Первая страница | 795 |
| Последняя страница | 800 |
| Аффилиация | C Changkang; Clarendon Lab., Oxford Univ., UK |
| Аффилиация | A J S Chowdhury; Clarendon Lab., Oxford Univ., UK |
| Аффилиация | H Yongle; Clarendon Lab., Oxford Univ., UK |
| Аффилиация | M Spears; Clarendon Lab., Oxford Univ., UK |
| Аффилиация | J W Hodby; Clarendon Lab., Oxford Univ., UK |
| Аффилиация | B M Wanklyn; Clarendon Lab., Oxford Univ., UK |
| Выпуск | 11 |
