Dielectric properties and relaxor behavior of La-doped Ba_0.5Sr_0.5TiO₃ ceramics sintered in nitrogen atmosphere

Ba(0.5-1.5x)Sr0.5LaxTiO3(x = 0.005,0.01,0.015,0.02) ceramics were manufactured in N-2 atmosphere by solid state reaction method. All ceramic samples present a cubic perovskite phase. The relative dielectric constant of the sample can reach 115,648 at 1000 Hz and 25 & DEG;C when x = 0.01, with a dielectric loss of less than 0.04 and a relatively high dielectric temperature stability in a region of 25-250 & DEG;C. The same sample experiences a decline in dielectric constant when it is annealed in air. In addition, there is an increase in its dielectric loss, with two sets of dielectric loss peaks. According to the systematic analysis, both the thermal motion of the oxygen vacancy and its defective dipole are responsible for the relaxation behavior. This may serve as a reference for the future study of the dielectric properties of modified materials.