Abstract
The crystal structures of two samples with nominal compositions of GaSr2(Tm0.7Ca0.3)Cu2Oz and (Ga0.65Co0.35)Sr2(Tm0.7Ca0.3)Cu2Oz have been analyzed by using neutron powder diffraction techniques to clarify the structural mechanisms associated with changes in superconducting behavior. Unlike for the Co-free sample, which does not show superconductivity, the Co-doped sample exhibits superconductivity around 45 K. The Rietveld refinement data reveal that both samples exhibit the 1212 structure with space group Ima2 and the Co atoms exclusively substitute for the Ga atoms in the GaO4 tetrahedron located on the chain sites of the 123 parent structure. The improvement in Tc of the Co-doped sample, compared to that of the undoped sample, is discussed in connection with the change in structural disorder and the change in hole concentration on the superconducting planes.
Sign-in/Register to access full text options 
Free) 
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 call
