Abstract
Two TlCa 2Ba 2Cu 3O 9−δ (Tl-1223) single crystals have been sequentially annealed in flowing oxygen or nitrogen and the complete crystal structure determined by leastsquares refinement of Mo Kα X-ray diffraction data. Small atomic displacements are consistent with a model in which small amounts of Tl 1+ present in the TlO layer are reversibly oxidized to Tl 3+ during mild oxygen anneals. Further, the disordered location of the Tl position off the four-fold, as determined by the usual least-squares refinement of X-ray data, appears to be related to the amount of oxygen present in the TlO layer in the particular crystal. Despite substantial changes in oxygen content in the TlO layers with annealing, Meissner data show very modest shifts in the superconducting transition temperature. T c's are 117 K after extended oxygen anneals and 121 K for nitrogen anneals, suggesting little change in the carrier concentration in the CuO 2 planes.
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.
