Fabrication and ferroelectric/dielectric properties of La-doped PMN-PT ceramics with high optical transmittance

Relaxor ferroelectric 0.75(Pb1_-3x/2Lax)(Mg1/3Nb2/3)O-3-0.25(Pb1-3x/La-2(x))TiO3 (La3+:PMN-PT x/75/25, where x=2.8, 3.0, 3.5, and 4.0 mol% of La3+) transparent ceramics were fabricated by the combination of oxygen atmosphere pressureless sintering and hot-pressing sintering process. The optical transmittances of above four ceramics are higher than 60% at the wavelength of 500-900 nm. La3+ :PMN-PT 3.0/75/25 exhibits the highest transparency around 70% at 900 nm which is very close to the theoretical transmittance 71%. Each of the four ceramics exhibits the pure perovskite phases. They show fully dense microstructures and their relative densities are higher than 99.8%. The ferroelectric and dielectric measurements indicate that these four ceramics exhibit relaxation characteristics. With increasing La3+ content, (200) peak in XRD patterns shifts to higher angles and the average grain size increases, while the temperature T epsilon(max) corresponding to the maximum epsilon(r), the remanent polarizations P-r and coercive fields E-c decrease gradually.