Lattice dynamics of Y0.9Pr0.1Ba2Cu3O7−δ

Abstract We find that the dynamics of the chain in both pristine YBCO as well in the Pr-doped material is determined by the oscillatio of chain oxygen atoms (namely O(4) atoms) between the two potential wells on either side of the chain. In addition, the oscillations of O(4) atoms are considerably modified at about 230 K, the temperature at which a phase transition has been reported in the literature. The substitution of Y by Pr does not affect the hole density along the chains as probed by the chemical shifts of the major species. This does not support the possibility of hole-filling by electron donation from Pr 3+ . However, even modest Pr substitution of 10% lowers considerably the enthalpy of interconversion of the two forms of the 5-coordinated species. These configurations around the minuscule amount of 57 Co are aquired with the help of an extraneous oxygen in the O(5) position.