Abstract
Abstract The high-temperature superconductor Bi2Sr2CaCu2Oy is known to have incommensurate modulated structure. Effect of Pr-doping on the structure of Bi-2212 system was studied. In this experiment, we prepared bulk sample of Bi2Sr2PrCu2Oy by solid state chemical reaction method. The single crystal of Bi2Sr2PrCu2Oy was also grown by the traveling solvent floating zone method (TSFZ). Rietveld analysis shows the bulk samples mainly contain impurity phase of Bi2201 and some peaks which were due to the modulated structure also appeared in the powder X-ray diffraction pattern. Two extra oxygen atoms are taken into account for the modulation in the bismuth oxide plane. The main (average) structure of Bi2Sr2PrCu2Oy is analyzed and the result shows that the crystal belongs to orthorhombic Amaa with the cell parameters: a = 5.487(1)A, b = 5.507(1)A and c = 30.328(4)A. Single crystal X-ray diffraction patterns were obtained, using the Weissenberg camera with 1A X-ray radiation in Photon Factory, Japan. By the analysis of Weissenberg photograph, the main structure and modulated structure in reciprocal space are plotted, the cell parameters are a = 5.489(2)A, b =5.526(5)A and c = 30.420(7)A and the crystal has one-dimensional modulation vector q = 0.243(2)b* + c*.