Article ID Journal Published Year Pages File Type
1608188 Journal of Alloys and Compounds 2015 6 Pages PDF
Abstract
A series of samples with the nominal composition of Bi2Sr2−xCaxCuO6+δ (x = 0.2, 0.4, 0.6, 0.8, 1.0) ceramics are synthesized by sol-gel growth. The microstructure and the incommensurate modulation structure (IMS) were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) methods. The superconductivity and the onset temperature of superconducting transition (Tc,onset) were analysed. In the whole Ca-doping range, an IMS in b∗-c∗ planes can be identified and the values of Tc,onset are all exceed 80 K. With an increase of x, the b-component of modulation vector q∗, the basic structural parameters b and c of Bi-2201 phase have a trend of fall first then rise, whereas the c-component of modulation vector, the angle θ between q∗ and b∗ vectors and the values of Tc,onset are reversely varied. It can be verified that Ca concentration x = 0.6 is an extreme value, at which the distortion of the CuO2 layers makes the concentration of mobile carriers and the value of Tc,onset optimizing.
Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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