Textured crystal growth of Bi(Pb)2212 bulk ceramics in high magnetic field

A systematic investigation has been made on the textured crystal growth of Bi(Pb)2212 bulk ceramics in high magnetic field. According to X-ray diffraction and microstructure analysis, a 9 T magnetic field is found to have an obvious tendency to orient Bi(Pb)2212 grains with their c-axis parallel to it in magnetic melt process (MMP). Bi(Pb)2212 single-phased bulk ceramics with an anisotropy of a factor of two in magnetization can be obtained by MMP while the microstructure and superconducting properties of the ceramics depend greatly on the preparing process. A two-step synthesis method, in which Bi(Pb)2212 is formed by the reaction between Bi(Pb)2201 and CaCuO2 powders in partial melting, is found especially useful for improving the density of the ceramics solidified from partial melting. The grain coupling strength and the crystal growth is also influenced greatly by the temperature profile of heat treatment, especially by the cooling rate during solidification and the maximum temperature in partial melting. (C) 1999 Elsevier Science B.V, All rights reserved.