In-plane lattice expansion anomalies of untwinned single crystals of YBa 2Cu 3O 7− δ superconductor

Abstract

The Anisotropic lattice expansion of untwinned single crystals of YBa 2Cu 3O 7− δ was measured by a high resolution x-ray diffraction technique. Several slope discontinuities including ones near T c were observed. In comparison to the recent internal friction studies, it was found that every lattice expansion anomaly seen in a and b axes has a corresponding internal friction peak. In particular, the internal friction anomalies near T c is consistent with the Akhieser effect, indicating that the slope discontinuity and the internal friction anomaly have the same microscopic origin, i.e., lattice fluctuations.