The Ba(ZrxTi1−x)O3 (BZT) thin films were prepared by deposition of relevant materials on LaNiO3-coated silicon substrates by the sol-gel process. The films thus prepared show a (100) preferred orientation in structure and vary with zirconium content. With the addition of Zr, the grain sizes of films were found to decrease, whereas their microstructure became dense. The changes in the films' grain sizes and microstructure were attributed to the addition of Zr to the BaTiO3 lattice. Dielectric constant measurements revealed that the thin films show a relaxor behaviour and have a diffuse phase tranition characteristic when x is 0.35. The hysteresis loops of the dielectric properties of films measured at room temperature were considered to be the result of the polarization state of the domains in these films in both the ferroelectric or paraelectric state. This leads to a distribution of Curie temperatures. The highest figure of merit value, K, was found for the BZT thin film with a very low dielectric constant. This indicates that BZT films have the potential to be used as microwave tunable devices with superior performance.

Sol-gel derived (Pb,La)(Zr,Sn,Ti)O3 powders and sintered ceramics were prepared; their crystallization kinetics and dielectric properties were studied as a function of temperature. X-ray powder diffraction showed that the pyrochlore phase formed initially from an amorphous gel during low-temperature heat treatment around 200-300℃. Further heat treatment to 600℃ resulted in the development of the perovskite phase with no significant growth of pyrochlore crystallites. At intermediate temperatures the sol-gel derived powders yielded a mixture of pyrochlore and perovskite phases. The crystallization kinetics of the perovskite phase was analyzed following the Avrami approach, which indicated that the process is diffusion limited. Those fine powders were utilized to prepare compact ceramics after sintering at various temperatures; their dielectric properties were analyzed. The electric field induced transformation from the antiferroelectric to the ferroelectric phase was clearly observed through the polarization reversal experiments. This material holds great promise for high energy density capacitors and microelectromechanical devices.

Antiferroelectric (Pb,Nb)(Zr,Sn,Ti)O3 thin films were deposited via a sol-gel process on LaNiO3-coated silicon substrates. Films showed a strong (001) preferred orientation upon annealing at 500-700℃ for 30min. The dependence of electrical properties on film thickness has been studied, with the emphasis placed on field-induced phase switching from the antiferroelectric to the ferroelectric state. The decrease of film thickness led to an increase of the phase-switching field along with the appearance of remanent polarization. However, the dielectric constant and maximum polarization decreased with the reduction of film thickness. Saturation polarization was 35mC/cm2, which is equal to that observed in bulk samples.

Ba(Zr0.35Ti0.65)O3 (BZT) thin films were deposited via a sol-gel process on Pt-coated silicon substrates. The BZT films were in the perovskite phase and had polycrystalline structure. Temperature-dependent dielectric measurements revealed that the thin films have relaxor behavior and diffuse phase transition characteristics. The tunability K of the dielectric constant (at 600kV/cm) is about 40% in the temperature range of 179-293K. The improved temperature stability from this BZT thin film is beneficial to applications requiring a wide range of operating temperatures, thereby eliminating the need for environmental controls. Although the K value is not extraordinarily large compared to (Ba,Sr!TiO3, the low dielectric constant of BZT is attractive for microwave frequency applications. This provides an additional possibility in balancing K and dielectric constant through materials engineering for optimum device performance.