Infrared dielectric response of the La2/3TiO3–LaAlO3 microwave ceramics system

Room temperature infrared reflectivity and near-millimetre transmission of (La2/3TiO3)1−x(LaAlO3)x (LTA−x) perovskite microwave ceramic system for x=0.04, 0.06, 0.1, 0.3 and 0.5 was measured and evaluated to obtain the complex dielectric function and optical conductivity. Polar phonon parameters were determined, discussed and compared with those recently found for the conducting perovskite LaTiO3. LTA−x is a low loss high permittivity dielectric with no dispersion of permittivity between 109 and 1012 Hz range. In this range the dielectric losses increase roughly proportionally to frequency, as expected from the theory. This fact together with the low value of the losses indicates that the extrinsic losses were mainly suppressed during the processing and the remaining microwave losses are predominantly intrinsic