Unraveling dielectric and electrical properties of ultralow-loss lead magnesium niobate titanate pyrochlore dielectric thin films for capacitive applications

摘要: PbO–MgO–Nb2O5–TiO2 (PMNT) pyrochlore thin films were prepared on Pt-coated silicon substrates by radio-frequency magnetron sputtering and postdeposition annealing method. Very interestingly, these pyrochlore-structured PMNT exhibited ultralow dielectric losses, with a typical loss tangent as low 0.001, relatively high constants, typically er∼170. It was found that the relative permittivity slightly but continuously increased upon cooling without any signature of structural phase transition, displaying quantum paraelectriclike behavior; meanwhile, did not show noticeable dispersion in real part over wide temperature range (77–400 K). Their responses could, however, be efficiently tuned applying dc electric field. A maximum applied bias field 1 MV/cm resulted ∼20% tunability permittivity, giving rise to fairly large coefficient nonlinearity, ∼2.5×...