Crystallization of Bi–Sr–Ca–Cu–O glasses in oxygen

A detailed study of the crystallization process for compositions near Bi 2 Sr 2 Ca 1 Cu 2 O y was undertaken using differential thermal analysis (DTA), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD). Glasses prepared by a splat-quench technique were free of secondary phases in most cases. A two-step crystallization process in oxygen was observed in which partial crystallization of the glass occurs initially with the nucleation of “2201” and Cu 2 O, and is completed with the formation of SrO, CaO, and Bi 2 Sr 3− x Ca x O y . No specific thermal event could be associated with the formation of the “2212” phase. Rather, formation occurs via conversion of 2201 into 2212. This was a kinetically limited process at temperatures below 800 °C as other phases were found to evolve in addition to the 2212 phase during extended anneals. In contrast, a nearly full conversion to the 2212 phase occurred after only 1 min of annealing at 800 °C and above. However, changes in resistivity data, secondary phases, and the measured 2212 composition upon extended anneals at 865 °C showed that considerably longer heat treatments were necessary for the sample to reach its equilibrium state.

[1]  T. Mason,et al.  Solid‐Solution Ranges of the n= 2 and n= 3 Superconducting Phases in Bi2(SrxCa1 −x)n+1CunOy and the Effect on Tc , 1991 .

[2]  C. Kim,et al.  Superconducting Glass-Ceramics in the Bi-Sr-Ca-Cu-O System , 1990 .

[3]  C. Rawn,et al.  Phase Equilibria and Crystal Chemistry in Portions of the System SrO-CaO-Bi2O3-CuO, Part II—The System SrO-Bi2O3-CuO , 1990, Journal of research of the National Institute of Standards and Technology.

[4]  S. Lebeau,et al.  Crystallization of amorphous Bi cuprate fibers to superconducting Bi2Sr2Ca1Cu2O8 , 1990 .

[5]  K. Nassau,et al.  Rapidly quenched Bi-containing high T sub c superconducting oxide compositions , 1989 .

[6]  C. Rawn,et al.  Phase Equilibria of the System SrO‐CaO‐CuO , 1989 .

[7]  M. Koike,et al.  Crystallization from a Glassy State in the Bi-Sr-Ca-Cu-O System , 1989 .

[8]  H. Nasu,et al.  Preparation and Crystallization Process of the High-Tc Superconducting Phase (Tc(end)>100 K) in Bi, Pb-Sr-Ca-Cu-O Glass-Ceramics , 1989 .

[9]  Tetsuro Nakamura,et al.  Preparation of Bi2Sr2CaCu2Ox Superconductors from Amorphous Films by Rapid Quenching after Rapid Melting , 1988 .

[10]  J. Waszczak,et al.  A new layered cuprate structure-type, (A1−xA′x)14Cu24O41 , 1988 .

[11]  Marshall,et al.  Structure and physical properties of single crystals of the 84-K superconductor Bi2.2Sr2Ca0.8Cu2O8+ delta. , 1988, Physical review. B, Condensed matter.

[12]  Gallagher,et al.  Crystallographic, thermodynamic, and transport properties of the Bi2Sr3-xCaxCu2O8+ delta superconductor. , 1988, Physical review. B, Condensed matter.

[13]  T. Komatsu,et al.  High-Tc Superconducting Glass Ceramics Based on the Bi-Ca-Sr-Cu-O System , 1988 .

[14]  T. Komatsu,et al.  Preparation of High-T_c Superconducting Bi-Pb-Sr-Ca-Cu-O Ceramics by the Melt Quenching Method : Electrical Properties of Condensed Matter , 1988 .

[15]  K. Gray,et al.  Superconductivity in thin films of the Bi−Ca−Sr−Cu−O system , 1988 .

[16]  M. Fukutomi,et al.  A New High-Tc Oxide Superconductor without a Rare Earth Element , 1988 .

[17]  H. Rawson.  Inorganic Glass Forming Systems , 1967 .