Piezoelectric materials Pb(In12 /Nb12 /)O3-Pb(Mg13/Nb23/)O3 -PbTiO3 with high Curie temperatures and large piezoelectric constants

Piezoelectric ceramics and single crystals of xPb(In₁2 /Nb₁2 /)O₃-yPb(Mg₁3/Nb₂3/)O₃-zPbTiO₃ (PIMNT100x/100y/100z) ternary systems have been investigated in order to develop a new piezoelectric material with high Curie temperature, Tc. Firstly, large coupling factor, kp=67%, piezoelectric constant, d₃₃=510 pC/N, and relatively high Tc=197°C of PIMNT 16/51/33 ceramic were confirmed. Secondly, PIMNT single crystals were grown by the flux method and the solution Bridgman method using a PbO-B₂O₃ flux and their electrical properties were confirmed. The selected composition was PIMNT 16/51/33. The obtained crystals had excellent electrical properties in the [001] plane: the dielectric constant ε₃₃^T /ε₀=4000, piezoelectric constant d₃₃=2200 pC/N, coupling factor k₃₃´=80%, which are almost the same as those of the PZNT 91/9 and PMNT 68/32 single crystals. Moreover, they had a large coercive field, Ec=7.0 kV/cm, due to the high Tc=187°C, which is about 1.5 times greater than that of the PMNT 68/32 single crystal and a high frequency constant, N₃₃´r=1160 Hzm, which is 1.4 times higher than that of the PZNT 91/9 single crystal. In view of their large coercive field and high frequency constant, single crystals of PIMNT 16/51/33 are a candidate piezoelectric material with a wide application field.