Far Infrared Spectroscopy of RBa2Cu3Ox with Variations in R and x

ABSTRACTWe report far infrared reflectance measurements of RBa2Cu3Ox, where R-Y, Er and Nd and 6<×<7 for YBa2Cu3Ox. Based on these measurements we assign the observed phonon features. In particular, one vibration is clearly identified as an R vibration, while the lowest energy mode (near 151 cm-1) is associated with the linear Cu-O chains.