Dielectric and pyroelectric properties in the La-doped 0.45Pb(Mg/sub 1/3/Ta/sub 2/3/)O/sub 3/-0.55PbZrO/sub 3/ system

Dielectric and pyroelectric properties of relaxor ferroelectric in the 0.45(Pb/sub 1-3x/2/La/sub x/)(Mg/sub 1/3/Ta/sub 2/3/)O/sub 3/-0.55PbZrO/sub 3/ solid solution series have been investigated. The dielectric constant and loss of ceramic samples were determined. The pyroelectric coefficient and spontaneous polarization were measured by the static Byer-Roundy method as a function of temperature and for various compositions in the La-doped PMT-PZ system. The addition of La/sub 2/O/sub 3/ was less effective in grain growth and shifting of the T/sub c//spl sim/12/spl deg/C/mole% downward in PMT-PZ system. Dielectric and pyroelectric properties of this system were improved by adding a small amount of La/sub 2/O/sub 3/. Compositions near 0.45PMT-0.55 PZ-0.04La have been identified to have high pyroelectric figures of merit near room temperature.