Electromechanical and electro-optic properties of xBiScO 3– yBiGaO 3–(1− x− y)PbTiO 3 single crystals

Abstract

Single crystals in the xBiScO 3– yBiGaO 3–(1− x− y)PbTiO 3 (BS–BG–PT) system were grown by the high temperature solution method using Pb 3O 4 and Bi 2O 3 as the flux. The dielectric permittivity ( ε r ) at room temperature for unpoled tetragonal crystals was determined to be 500–600 with dielectric loss tangents less than 0.3%. The Curie temperature was found to be around ∼420–450°C, with a dielectric maximum, exhibiting relaxor behavior. The longitudinal piezoelectric coefficient ( d 33) was found to be ∼300 pC/N for 〈0 0 1〉 oriented tetragonal crystals with electromechanical coupling factor ( k 33) of 75%, with a shear mode, d 15∼290 pC/N and k 15∼45%, lateral mode, d 31∼−55 pC/N and k 31∼−37%. The remnant polarization ( P r) was 46 μC/cm 2 with a coercive field ( E c) of 43 kV/cm at 1 Hz and DC field of 60 kV/cm. The linear electro-optic (E-O) coefficients of poled crystals determined using an automated scanning Mach–Zehnder interferometer method at room temperature and wavelength of 632.8 nm were r 33=36 and r 13=4 pm/V, respectively.