Abstract
YBa2(Cu1-xAgx)4O8 (x<0.1) superconductor was synthesized under high oxygen partial pressures by oxygen hot isostatic press. From Raman scattering spectroscopy, the phonon frequency of O(4)-Cu(1) stretching vibration increased and that of O(1)-Cu(1) vibration decreased by doping silver. Phonon frequency change is due to an increase in the force constant of O(4)-Cu(1) bond and to a decrease in the force constant of O(1)-Cu(1) bond by a silver replacement into the Cu(1) site. Ag-O bondings are detected in the 124 phase by an infrared absorption spectroscopy also. The evidence of silver replacement into Cu(1) site in YBa2Cu4O8 was presented for the first time.
