Sol-gel synthesis, structure, and dielectric properties of La0.67LixTi1-xAlxO3 solid solutions

La0.67LixTi1-xAlxO3 were synthesized using the sol-gel Pechini route. Ceramic samples were sin -tered in the temperature range of 1240-1300 degrees C in the air atmosphere. It was found that in the concentration range of 0.05 < x < 0.15 there is a morphotropic phase boundary region with rhombohedral and tetragonal syngonies. In the concentration range of 0.15 < x < 0.3, a single-phase solid solution with rhombohedral R 3 c syngony is formed. As the value of x increases, the average grain size of La0.67LixTi1-xAlxO3 ceramics increases from 5.23 mu m (x = 0.05) to 8.76 mu m (x = 0.3). All materials of the La0.67LixTi1-xAlxO3 system at 0.05 < x < 0.3 have colossal values of dielectric constant epsilon ' > 104 at frequencies up to 1 kHz. La0.67LixTi1-xAlxO3 (x = 0.2) solid solution with rhombohedral syngony has the highest value of dielectric constant and the lowest value of the dielectric losses.

Automated summary

La0.67LixTi1-xAlxO3 ceramics were synthesized and the phase characteristics were studied. A morphotropic phase boundary of rhombohedral and tetragonal symmetries was observed in the concentration range of 0.05 < x < 0.15, while a single-phase solid solution with rhombohedral R 3 c symmetries was formed in the concentration range of 0.15 < x < 0.3. The average grain size of La0.67LixTi1-xAlxO3 ceramics increased from 5.23 μm to 8.76 μm as the value of x increased. The dielectric constant of all materials in the La0.67LixTi1-xAlxO3 system at 0.05 < x < 0.3 was found to be greater than 104 at frequencies up to 1 kHz, with the highest value observed for La0.67LixTi1-xAlxO3 (x = 0.2) solid solution with rhombohedral symmetry.