Abstract
Samples with nominal composition Tl x Ba 2Cu 2O 6 where x = 0.5, 1.0, 1.5, 1.75, 2.0, 2.5 and 3.0 were calcined at 890°C for 10 h and sintered at various temperatures for 3 1 2 min. X-ray powder diffraction patterns of all the samples show the characteristics of the 2201 phase which suggests the transformation of all the nominal compositions to 2201 phase. In some cases extra peaks due to BaCuO 2 and Tl 2O 3 are also present. The samples having Tl contents 1.5, 1.75 and 2.0 are monophase material with unit cell parameters a = 3.86 A ̊ , c = 23.20±0.02 A ̊ . The overall symmetry is tetragonal. All the lines are indexible on the I4/mmm space group. Samples with Tl content 1.5-2.0, sintered at 930–950°C, show the best superconducting properties. The highest T c is obtained in Tl 2.0 and the highest Meissner fraction in Tl 1.5. Chemical analysis indicates Tl deficiency in all the samples, which suggests substitution of Tl 3+ by Cu 1+ or Cu 2+ and oxidation of copper to Cu 3+, which increases monotonically with T c. Tl contents in optimum samples lie in the range 1.14-1.82 and oxygen content varies from 5.6-6.1
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
