CRYSTAL GROWTH OF Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 AND Pb(Sc1 /2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 PIEZOELECTRIC SINGLE CRYSTALS USING THE SOLUTION BRIDGMAN METHOD

The crystal growth of xPb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)-zPbTiO3 (PIMNT 100x/100y/100z) and x'Pb(Sc1/2Nb1/2)O3-y'Pb(Mg1/3Nb2/3)-z'PbTiO3 (PSMNT 100x'/100y'/100z') ternary systems was investigated by the solution Bridgman method using PbO-B2O3 flux. A PIMNT single crystal 25 mm in diameter and 30 mm in length was grown at the bottom of a platinum crucible; the highest temperature was 1250 C and the growth rate was 0.4 mm/h. On the other hand, the PSMNT single crystals were multinucleated under the same growth conditions. The results obtained using EPMA revealed that Ti content increased gradually from the crystal part near the bottom of the crucible for the PIMNT and PSMNT single crystals. Although the In/Mg ratio was relatively constant in the PIMNT, the Sc/Mg ratio varied in the PSMNT crystals. The Curie temperature, Tc, of the PIMNT single crystal ranged from 181 C to 196 C. The dielectric constant after poling, e33T/e0=3,630, coercive field of Ec=7.0 kV /cm, electromechanical coupling factors sliver mode, k'33=80.3%, and frequency constant, N'33r=1,110 Hz m, were confirmed for the PIMNT single crystal with Tc=191 C. 21 refs.