Multilayer thin films with compositional PbZr_0.52Ti_0.48O₃/Bi_1.5Zn_1.0Nb_1.5O₇ layers for tunable applications

摘要

The dielectric properties and tunability of multilayer thin films with compositional PbZr_0.52Ti_0.48O₃/Bi_1.5Zn_1.0Nb_1.5O₇ (PZT/BZN) layers (PPBLs) fabricated by pulsed laser deposition on Pt/TiO₂/SiO₂/Si substrate have been investigated. Dielectric measurements indicate that the PZT/BZN bilayer thin films exhibit medium dielectric constant of about 490, low loss tangent of 0.017, and superior tunable dielectric properties (tunability?=?49.7% at 500?kV/cm) at a PZT/BZN thickness ratio of 3, while the largest figure of merit is obtained as 51.8. The thickness effect is discussed with a series connection model of bilayer capacitors, and the calculated dielectric constant and loss tangent are obtained. Furthermore, five kinds of thin–film samples comprising single bilayers, two, three, four and five PPBLs were also elaborated with the final same thickness. The four PPBLs show the largest dielectric constant of ~538 and tunability of 53.3% at a maximum applied bias field of 500?kV/cm and the lowest loss tangent of ~0.015, while the largest figure of merit is 65.6. The results indicate that four PPBLs are excellent candidates for applications of tunable devices.