Open AccessSTUDY OF THE MONOCLINIC PHASE AND EFFECT OF Ba-DOPING IN Bi-Sr-Ca-Cu-O SYSTEM
Author(s) -
Zhiqiang Mao,
Han Zhiyi,
Wei Yu,
Yang Li,
Lu Jiang,
Caimei Fan,
Guien Zhou,
Zhaojia Chen,
Yuheng Zhang
Publication year - 1991
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.40.815
Subject(s) - monoclinic crystal system , materials science , diamagnetism , superstructure , phase (matter) , microstructure , ion , crystallography , superconductivity , doping , crystal structure , analytical chemistry (journal) , condensed matter physics , chemistry , physics , magnetic field , thermodynamics , composite material , optoelectronics , organic chemistry , chromatography , quantum mechanics
The sample with the nominal composition Bi2Sr2Ca1-xBaxCu2Oy(A),Bi1.7Pb0.3Sr2Ca2-xBaxCu3Oy(B) were synthesized by solid state reaction. The analyses of phases and structure of the samples showed that a new kind of monoclinic phase exists in Bi-system with cell dimension a=24.84?, b=6.29?, c = 20.70?, β=114.2?. There exists special relation between the monoclinic phase and the superconducting property of Bi system. For 2212 phase, the diamagnetic transition at 95K was observed when the monolinic phase co-existed with 2212 phase, furthermore the addition of Ba ions facilitated the formation of the monoclinic phase. For Ba-doped 2223 phase, the study of electron diffraction indicated that Ba ions got into the 2223 phase and caused the change of crysral micro-structure of 2223 phase, a new additional superstructure appeared along b axis, and two kinds of modulation mode were observed simultaneously along this direction, the wavelength of which is 27?, 43? respectively. The measurement of physical property showed that the zero resistance temperature of the samples can reach as high as 113-114K by proper doping of Ba ions, and the diamagnetic transtion at 118K was also observed. This kind of increasing of the critical temperature of 2223 phase may be related to changes of its crystal microstructure.