The main focus of this thesis is the study of a novel microwave component, the tunable thin film bulk acoustic wave resonator (TFBAR), based on ferroelectric BaxSr1−xTiO3 thin films. Conventional fixed frequency TFBARs, widely used for filtering applications in wireless communication systems, are based on ordinary piezoelectrics. The tunable TFBAR on the other hand utilizes the dc field induced...

Ferroelectric materials are characterized by spontaneous electric polarization that can be reversed by inverting an external electric field. Owing to their unique properties, ferroelectric materials have found broad applications in microelectronics, computers, and transducers. Water molecules are dipolar and thus ferroelectric alignment of water molecules is conceivable when water freezes into ...

We use in situ transmission electron microscopy to directly observe, at high temporal and spatial resolution, the interaction of ferroelectric domains and dislocation networks within BiFeO3 thin films. The experimental observations are compared with a phase field model constructed to simulate the dynamics of domains in the presence of dislocations and their resulting strain fields. We demonstra...

Adv. Mater. 2009, 21, 817–823 2009 WILEY-VCH Verlag Gm Multiferroic BiFeO3 has attracted great interest due to its promising application tomagnetoelectric devices. In addition, the high remanent polarization and piezoelectric response of BiFeO3 thin films, which are comparable to those of conventional Ti-rich lead zirconia titanate, suggested BiFeO3 as a strong candidate for lead-free nonvolati...

The Letter by Dawber et al. [J. Phys.: Condens. Matter 15 L393 (2003)] notes that incomplete screening in the electrodes of a ferroelectric capacitor can result in an underestimate for the true coercive field in films of nanometer thickness. We show that their estimate of the magnitude of this correction it too large in the case of ferroelectric copolymer LangmuirBlodgett films and, as a result...

Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as-grown thin films or after a post-deposition rapid thermal annealing (RTA) treatment performed at 600 °C for different lengths of time (1 and 5 min) in an...

Bi3.25Nd0.75Ti3O12 (BNT) ferroelectric thin films with a thickness of f0.5 Am, on substrates of Pt/Ti/SiO2/Si, (100) SrTiO3 and (100) MgO, with a 0.4-Am-thick La0.7Sr0.3MnO3 (LSMO) layer as bottom electrode, were deposited via pulsed laser deposition. The multilayer thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurement. The LSMO ...

We have studied the effect of misfit strain on the microstructure and properties of ferroelectric lead zirconate titanate thin films. We have changed the misfit strain by varying the film thickness and studied the thickness effect on the domain formation of epitaxial PbZr0.2Ti0.8O3 ~PZT! films grown by pulsed laser deposition on ~001! LaAlO3 substrates with La0.5Sr0.5CoO3 ~LSCO! electrodes. The...

This paper aims at improving the performance of the poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer for pyroelectric infrared detection and direct thermal to electrical energy conversion. Three different types of samples were prepared and examined: commercial, purified and porous films. Here, full characterization of the thermophysical and electrical properties relevant to p...

We report the structural and superconducting properties of FeSe0.3Te0.7 (FST) thin films with different thicknesses grown on ferroelectric Pb(Mg1/3Nb2/3)0.7Ti0.3O3 substrates. It was shown that the FST films undergo biaxial tensile strains which are fully relaxed for films with thicknesses above 200 nm. Electrical transport measurements reveal that the ultrathin films exhibit an insulating beha...