摘要
Bi_(2)Sr_(2)CaCu_(2)O_(y) single crystals were air-annealed at 300,400,600 and 750℃ for 20h in consequence.Measurements of ac susceptibility and x-ray diffraction showed that at annealing temperature below 400℃,the change of Tc was dominated by oxygen-diffusion involved in pervoskite unit and was strongly sample-dependent.This diffusion from pervoskite unit occurred earlier than that from Bi-O layers.At annealing temperature over 400℃,with the intercalation of excess oxygen into Bi-O layers,the hole concentration in the crystal was redistributed so that Bi-O reservoir fully determined superconductivity.From the changes of non-uniform strain in annealing process,it was found that structural modification was also closely correlated to superconductivity.
作者
赵小如
吴文彬
孙学峰
汪亮斌
周贵恩
李晓光
张裕恒
Koichi Kitazawa
ZHAO Xiao-ru;WU Wen-bin;SUN Xue-feng;WANG Liang-bin;ZHOU Gui-en;LI Xiao-Guang;ZHANG Yu-heng;Koichi Kitazawa(Structure Research Laboratory,University of Science and Technology of China,Hefei 230026;CCAST(World Laboratory),P.O.Box 8730,Beijing 100080;Department of Applied Chemistry,Department of Superconductivity,University of Tokyo,7-3-1 Hongo,Bunkyo 113,Japan)
基金
Supported by the National Natural Science Foundation of China under Grant No.59425008
the NationalCenter for Research&Development on Superconductivity under Grant No.AJ103.
