High-resolution electron microscopy and low-temperature electron diffraction studies of a Bi2212 single crystal grown by the floating zone method

Abstract

High-resolution electron microscopy of a Bi2Sr2CaCu208 (Bi2212) single crystal prepared by the floating zone method shows that the single crystal is of high quality; there is no intergrowth faulting in the layered structure along the c-axis. Low-temperature selected area diffraction and convergent beam electron diffraction (CBED) studies of this high-quality single crystal show that there is no detectable change for both the point group symmetry of the basic structure and the modulated structure from room temperature to about 15 K. However, a lattice anomaly around 215 K was suggested by measuring the temperature dependence of the ratio between the cross-point distances of the HOLZ lines in high-index CBED patterns. The presence of the lattice anomaly was further confirmed by low-temperature X-ray diffraction.KEY WORDS: Single crystal of Bi2Sr2CaCu208; high-resolution electron microscopy; low-temperature electron diffraction; lattice anomaly.