Defect-induced far-infrared absorption in oxygen-ion conductor (CeO2)(0.9)(CaO)(0.1)

The far-infrared (FIR) absorption of the oxygen-ion conductor (CeO2)(0.9)(C aO)(0.1) and for comparison, pure CeO2 ceramics, has been measured in the r egion 10-100 cm(-1) at 11 K and 297 K. Continuous FIR absorption showing a nearly quartic frequency dependence and two weak absorption bands at about 63 cm(-1) and 76 cm(-1) at 11K were found in the (CeO2)(0.9)(CaO)(0.1). It is considered that the continuous FIR absorption reflects the vibrational d ensity of states and the. two weak bands are due to oxygen-vacancy modes. T emperature and frequency changes of the FIR absorption in the (CeO2)(0.9)(C aO)(0.1) as a disordered solid solution exhibit non-glass-like behavior.