Internal friction study on bilayer cuprates Pr(Ba1−xSrx)2Cu3O7−δ

The internal friction of partially Sr-substituted Pr(Ba1−xSrx)2Cu3O7−δ (x = 0, 0.05, 0.1, 0.2, 0.3, and 0.4) ceramics was measured by the vibrating-reed method from liquid nitrogen temperature to room temperature at kilohertz frequencies. The intensity of the internal friction peak, which appears around 250 K, decreases upon Sr doping. The result is explained in terms of a possible combining structural freezing transition of CuO5 square pyramids and oxygen atoms in CuOx chains. Another internal friction peak around 134 K was observed in tetragonal Pr(Ba0.6Sr0.4)2Cu3O7−δ which is temporarily explained by the hopping of holes in the CuO2 layers.

Research highlights
► Internal friction of Pr(Ba1−xSrx)2Cu3O7−δ was analysised.
► Both the dynamics of CuO5 square pyramids and oxygen atoms in CuOx chains contributed to the internal friction peak around 250 K.
► The internal friction around 134 K is relating to the hopping of holes in tetragonal Pr(Ba0.6Sr0.4)2Cu3O7−δ.