{'fraction_non_alphanumeric': 0.048938134810710986, 'fraction_numerical': 0.032317636195752536, 'mean_word_length': 4.3399014778325125, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Large Anisotropy of the Upper Critical Magnetic Field in Single Crystal Bi-(Sr, Ca)-Cu-O

Single crystals of a recently discovered high-Tc Bi-(Sr, Ca)-Cu-O compound have been obtained. EPMA analysis exhibited that the compositional ratio of the crystal is 2-3-2. X-ray diffraction and transmission electron diffraction analysis revealed that the crystal has a layered structure characterized by orthorhombic symmetry with the lattice constant a=5.405 Å, b=5a and c=30.69 Å. The upper critical magnetic field Hc2 has been measured for the superconducting single crystal. The anisotropy between the c-axis and the basal plane is much larger than that of Ba2YCu3O7-y or (La1-xSrx)2CuO4-y. The slope of temperature dependence of Hc2 along the c-axis is -0.32 T/K, while that along the basal plane is -14±3 T/K. The coherence length along the c-axis is estimated to be 1.0±0.1 Å, and that in the basal plane is 42 Å. The anisotropy factor is 44±9. These values suggest that the two-dimensionality in electronic structure for this superconductor is much stronger than other high-Tc oxides.