Dielectric and piezoelectric properties for 0.62Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 single crystals

The dielectric and piezoelectric properties of 0.62Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 single crystal (PMNT62/38) were investigated in this work. Power X-ray diffraction demonstrated PMNT62/38 had a tetragonal structure at room temperature. The Curie temperature was 187 °C on heating. The poled and as-grown dielectric constants εr of [001] oriented PMNT62/38 at room temperature were ∼500 and ∼5000, respectively. The remanent polarization Pr and coercive field Ec for [001] oriented one were 34.2 μC/cm2 and 8.25 kV/cm, respectively. The strain at 15 kV/cm and −15k V/cm were 0.078 and 0.125%, respectively. The piezoelectric constant d33 was ∼350 pC/N. The electromechanical coupling coefficients; 0.89 of k33, 0.61 of kt, 0.46 of k31 and 0.45 of k15 were calculated from measured resonance and anti-resonance frequencies by impedance resonance techniques. In single domain process it was found the re-oriented domains of [001] poled PMNT62/38 were instable, which caused it hard to align the spontaneous polarizations to create a single domain crystal.