IMPROVEMENT OF CRYSTAL-GROWTH AND SUPERCONDUCTIVITY OF YBA2CU3O7-DELTA BY ADDITIVE

被引:11
作者
CHEN, CK
CHOWDHURY, AJS
HU, YL
SPEARS, M
HODBY, JW
WANKLYN, BM
机构
[1] Clarendon Lab., Oxford Univ.
关键词
D O I
10.1088/0953-2048/7/11/003
中图分类号
O59 [应用物理学];
学科分类号
摘要
A series of experiments have been carried out on the influence of additives on the crystal growth and superconductivity of YBa2Cu3O7-delta (YBCO) crystals grown in alumina crucibles from the eutectic self-flux system of BaO-CuO. The single additives were B2O3, Bi2O3, BaF2 or BaCl2 and the double additives were BaF2-B2O3 or BaF2-Bi2O3. It was found that a small amount of BaF2 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 x 10 x 0.5 or 12 x 10 x 1 mm(3) 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-c = 93 K with transition width < 1 K after annealing in oxygen have been reached by using BaF2 as additive. A model is proposed to interpret these improvements: it incorporates F- induced monomolecular clusters in the high-temperature solution and preferential adsorption of F- on the surface of the growing crystal.
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页码:795 / 800
页数:6
相关论文
共 14 条
[1]   PHYSICOCHEMICAL INVESTIGATIONS ON CRYSTAL-GROWTH OF OXIDE SUPERCONDUCTORS [J].
CHEN, CK .
PROGRESS IN CRYSTAL GROWTH AND CHARACTERIZATION OF MATERIALS, 1992, 24 (03) :213-267
[2]   CRYSTAL-GROWTH OF CUO FROM BAO FLUX [J].
CHEN, CK ;
HU, YL ;
WANKLYN, BM ;
HODBY, JW .
JOURNAL OF CRYSTAL GROWTH, 1993, 129 (1-2) :239-242
[3]   SELECTION OF APPROPRIATE SYSTEMS FOR FLUX GROWTH OF SINGLE-CRYSTAL YBA2CU3O7-Y [J].
CHEN, CK ;
HODBY, JW ;
HU, YL ;
WANKLYN, BM .
JOURNAL OF MATERIALS CHEMISTRY, 1994, 4 (03) :469-473
[4]   FLUORINE OXIDATION OF HIGH-TEMPERATURE SUPERCONDUCTORS [J].
CIRILLO, KM ;
WRIGHT, JC ;
SEUNTJENS, J ;
DAEUMLING, M ;
LARBALESTIER, DC .
SOLID STATE COMMUNICATIONS, 1988, 66 (12) :1237-1241
[5]  
DENIYANETS LN, 1991, SOV PHYS USP, V34, P36
[6]   SUPERCONDUCTIVITY IN THE SYSTEM (ALXY1-X)BA2CU3O6.5+DELTA [J].
FRANCK, JP ;
JUNG, J ;
MOHAMED, MAK .
PHYSICAL REVIEW B, 1987, 36 (04) :2308-2310
[7]   EFFECT OF FLUX COMPOSITION ON CRUCIBLE CORROSION AND ALUMINUM DISTRIBUTION COEFFICIENT IN YBCO SINGLE-CRYSTALS [J].
LICCI, F ;
FRIGERI, C ;
SCHEEL, HJ .
JOURNAL OF CRYSTAL GROWTH, 1991, 112 (2-3) :606-610
[8]   PHASE-EQUILIBRIUM DIAGRAM IN THE TERNARY-SYSTEM Y2O3-BAO-CUO [J].
OKA, K ;
NAKANE, K ;
ITO, M ;
SAITO, M ;
UNOKI, H .
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 1988, 27 (06) :L1065-L1067
[9]   ALUMINUM SUBSTITUTION IN BA2YCU3O7 [J].
SIEGRIST, T ;
SCHNEEMEYER, LF ;
WASZCZAK, JV ;
SINGH, NP ;
OPILA, RL ;
BATLOGG, B ;
RUPP, LW ;
MURPHY, DW .
PHYSICAL REVIEW B, 1987, 36 (16) :8365-8368
[10]   ATTEMPTS TO PREPARE FLUORINE CONTAINING YBA2CU3O6.5+DELTA [J].
TYAGI, AK ;
PATWE, SJ ;
RAO, URK ;
IYER, RM .
SOLID STATE COMMUNICATIONS, 1988, 65 (10) :1149-1151