GROWTH, CHARACTERIZATION, AND PHYSICAL-PROPERTIES OF BI-SR-CA-CU-O SUPERCONDUCTING WHISKERS

Single crystal whiskers of the Bi-based high-T-c superconductors have been grown directly from the stoichiometric melt. Conditions for the p referable growth of the (2212) phase and annealing conditions for the conversion from the (2212) phase to the (2223) and (2234) Bi-based sup erconducting phases are achieved. The orientation and chemical composi tion of the crystals were characterized by X-ray diffractometry and en ergy dispersive X-ray analysis. Characteristic structural properties o f the whiskers (incommensurable modulation in b-direction, peculiariti es of dislocation networks) have been revealed by transmission electro n microscopy and electron diffraction. Some special features of the br oad superconducting transition in multiphase whiskers have been examin ed by spatially resolved measurements using low-temperature scanning e lectron microscopy.