Anomalous atomic thermal oscillations during a phase transition in a superconducting state in Tl2Ba2CaCu2O8 monocrystals

X-ray diffraction studies showed anomalous behaviour of the structure parameters of the (Tl0.93Cu0.07)2Ba2 (Ca0.88Tl0.12)Cu2O8 monocrystal at Tc=110 K during transition in a superconducting state. Strong evidence for anomalous temperature dependence was seen in the parameters of atomic thermal oscillations, which testified to the changes in the valence and chemical bonds (electronic structure) of atoms, as well as to changes in the phonon spectra of crystal during the transition. 6 refs., 2 figs