TERAHERTZ FREQUENCY RANGE DIELECTRIC TUNABILITY OF Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ HETERO-PHASE SUPERLATTICES

ABSTRACT

Linear and nonlinear dielectric responses in the terahertz (THz) frequency range of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) hetero-phase superlattices (HPSLs) were studied. The results indicate a significant relaxation contribution to the recorded THz dielectric spectra from the formation of interface-associated nanoclusters and the variation of mean relaxation frequency respective to the material's maximum phase transition temperature. A large electric field induced dielectric tunability (so-called nonlinear dielectric property), which is as about 15% when the applied voltage reaches about 150 V, was recorded in the HPSL with the smallest superlattice period of 10 nm. This large tunability was partially attributed to both rexalation and the in-plane alignment of the used measurement configuration.