Dielectric and optical behaviors in relaxor ferroelectric Pb(In1/2Nb1/2)1−xTixO3 crystal

Dielectric permittivities (ε′,ε″) have been measured as functions of temperature (140–535 K) and frequency (500 Hz–2.0 MHz) in a (001)-cut Pb(In1/2Nb1/2)0.7Ti0.3O3 (PINT30%) single crystal grown by the modified Bridgman method with Pb(Mg1/3Nb2/3)0.71Ti0.29O3 (PMNT29%) seed crystal. A diffused phase transition was observed in the temperature region of ∼430–460 K with strong frequency dispersion. Above the Burns temperature TB≅510 K, the dielectric permittivity was found to follow the Curie–Weiss behavior, ε′=C/(T−TC), with parameters C=3.9×105 and TC=472 K. Below TB≅510 K, polar nanoclusters are considered to appear and are responsible for the diffused dielectric anomaly. Optical transmission, refractive indices, and the Cauchy equations were obtained as a function of wavelength at room temperature. The unpoled crystal shows almost no birefringence, indicating that the average structural symmetry is optically isotropic. The crystal exhibits a broad transparency in the wavelength range of ∼0.4–6.0 μm.