Atomic structure of Tl2Ba2CaCu2O8 single crystals before and after the transition to the superconducting state
Blomberg M. K., Merisalo M. Yu., Molchanov V. N., Tamazyan R. A., Simonov V. I.
The atomic structure of single crystals of the Tl 2212 phase at 296,160, and 60 К has been refined by x-ray structural analysis. The superconducting transition is accompanied by significant displacements of the atoms of the TIO layer and by anomalous changes in the Cu05 pyramids. The macroscopic symmetry of the crystal remains tetragonal as this phase transition occurs. The local orthorhombic distortions of the structure associated with displacements of Tl atoms occur before and after the phase transition.