FAR-INFRARED REFLECTIVITY SPECTRA OF CaTiO_3--Li1/2Sm1/2TiO_3 M1CROWAVE D1ELECTRICS

摘要

Microwave dielectric properties and far-infrared reflectivity spectra of the (l- y)CaTiO_3-yLi1/2Sm1/2TiO_3 ceramics were investigated in the range of 0.0 ≤ y ≤ l.0. The dielectric constant, unloaded Q value, and temperature coefficients of the resonant frequency (TCF) of the specimens decreased with increasing Li1/2Sm12/TiO_3. At y = 0.7, a nearly zero TCF value was obtained, with a high dielectric constant (K = ll4) and an unloaded Q (Q.f = 3700). Based on analysis of the far-infrared reflectivity spectra from the 50 to 4000 cm~-l range, which were evaluated using Kramers-Kronig analysis and the classical oscillator model, the change in the Q.f value and dielectric constant of the specimens could be explained by intrinsic factors such as ionic polar- ization and dielectric loss (tan δj). The relative tendency of calculated dielec- tric constant and Q.f values agreed well with that of the measured values.