Influences of Excess PbO on Optical Properties and Microstructures of La Modified 0.75Pb (Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-0.25PbTiO<sub>3</sub> Electro-Optic Transparent Ceramics

Abstract

La-modified 0.75Pb (Mg1/3Nb2/3)O3-0.25PbTiO3(PLMNT) electro-optic (EO) transparent ceramics were synthesized through a columbite precursor method. Excess PbO (10, 15 and 20 mol %) was added to study the effect on the transparency, electro-optic effect, and microstructures of PLMNT transparent ceramics. The phase structure of different samples can be identified as single perovskite structure with no second phase detected. The average grain size increased as the concentration of excess PbO increased from 10 mol% to 20 mol%. On the contrary, the transparency decreased with the increase of the concentration of excess PbO. When the concentration of excess PbO was 10 mol%, the transmittance was about 62% at 632.8nm. The EO coefficient was calculated through measuring the birefringence as a function of electric field. The EO coefficient increased with the increase of the concentration of excess PbO and the maximum EO coefficient reached 40.6×10-16(m/V)2 when the excess PbO was 20 mol%.