Publications by Nava Setter | EPFL Graph Search

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The piezoelectric properties of rhombohedral relaxor-ferroelectric compositions close to morphotropic phase boundary have been studied as a function of temperature. As they exhibit, upon heating, a rhombohedral to tetragonal phase transition the piezoelectric behavior changed with temperature. Large piezoelectric (d(33)) and coupling (k(33)) coefficients of 0.91 Pb(Zn1/3Nb2/3)O-3-0.09PbTiO(3) single crystals drop to usual ceramic values after crossing the transition. Intrinsic and reversible contributions t

The temperature coefficient of the dielectric permittivity (tau(epsilon)) of nonferroelectric complex perovskites is of importance in the application of these cermaics to microwave filters and resonators. Recent work has directly related changes in the tau(epsilon) of complex perovskites to the onset of structural phase transitions which involve tilting of the octahedra. It can be argued that the onset of octahedral tilting is controlled by the tolerance factor (t). Thus, a relationship between tau(epsilon)

The problem of the structure and energy of a charged 180-degree head-to-head domain wall is considered, using Landau theory. It was found that the scales controlling the wall structure can be very different from the Debye radius. Depending on the spontaneo ...

This paper discusses the mechanisms that can contribute to the enhanced longitudinal piezoelectric effect along nonpolar directions in perovskite crystals, such as BaTiO3, PbTiO3, KNbO3, Pb(Mg1/3Nb2/3)O-3-PbTiO3 and Pb(Zn1/2Nb2/3)O-3-PbTiO3. Piezoelectric ...

We consider the properties of charged domain walls in ferroelectrics as a quantum problem. This includes determination of self-consistent attracting 1D potential for compensating charge carriers, the number and positions of discrete energy levels in this p ...

Ferroelectrics are usually defined as polar materials that display polarisation hysteresis. This is a functional definition. A structural definition exists too, based solely on symmetry arguments. The structural definition, useful e.g. for design of new ma ...

Ferroelectric switching in circular and ring capacitors has been performed using a stroboscopic mode of piezoresponse force microscopy. A simple geometric model incorporating the characteristic domain wall motion is sufficient to describe the switching of ...

BaxSr1-xTiO3 (BST) and its composite films have been studied for the improvement of the tunable performances via nano-structual control. The strong correlation between strain and tunability similar to that between strain and permittivity was confirmed in t ...

Using Landau-Ginzburg-Devonshire theory and tetragonal BaTiO3 as an example, this letter demonstrates that strong electric bias fields applied antiparallel to spontaneous polarization may lead to a large enhancement of piezoelectric properties in monodomain perovskite crystals with multiple phase transitions. At temperatures close to tetragonal-orthorhombic phase transition, the largest enhancement is approximately along the [111] axis. The enhancement is due to the field induced dielectric softening of the

Pyroelectric thin-film point detectors and 1 x 12 arrays have been fabricated and characterized. They consist of sol-gel-deposited PZT thin-film elements on micromachined Si3N4/SiO2 membranes. The measured current and voltage response as a function of modulation frequency of a 1 x 12 array element is compared with finite-element calculations. Voltage responsivities of almost 3000 V W-1 in vacuum and 800 V W-1 in air have been achieved for 0.4 mm x 0.9 mm elements. Some point detectors have been completely p

Control of magnetic domain walls (DWs) and their propagation is among the most promising development directions for future information-storage devices. The well-established tools for such manipulation are the spin-torque transfer from electrical currents a ...

Charged domain walls in proper ferroelectrics were shown recently to possess metallic-like conductivity. Unlike conventional heterointerfaces, these walls can be displaced inside a dielectric by an electric field, which is of interest for future electronic ...

We fabricated and characterized a micromotor driven by a piezoelectric PZT (PbZrxTi1-xO3) thin films. Sputter and sol-gel techniques have been applied for the deposition of the PZT films onto a silicon stator membrane, which was 20 to 30 µm thick and had a diameter of 4 mm. The amplitudes of the membrane deflections are as large as 800 nm/V at the first resonance (26 kHz), and 60 nm/V at 1 Hz. The operation of the motor was obtained at 1 to 3 Vrms, with speeds of up to 200 rpm at 1.1 Vrms and torques of 35

(001)-epitaxial SrTiO3 films were grown on (La, Sr)(Al, Ta)O-3 substrates for investigating the impact of biaxial strain on the antiferrodistortive (AFD) structural phase transition in SrTiO3. The films were fully constrained by the substrates, which resulted in the large in-plane compressive strain of -0.9%. The AFD transition temperature estimated using temperature controlled x-ray diffraction and transmission electron microscope was over 150K higher than the theoretical prediction, but rather supported t

Pyroelectric PbTiO3 thin films devices with two temperature compensating elements on a SiO2/Si3N4 membranes have been fabricated and characterized. The measured voltage responsivity as a function of radiation modulation frequency has been compared to finite element model calculation. The relevant film properties have been compared for sputter and a sol-gel deposition techniques. The calculated responsivity amounts to 30 V/W. The measured pyroelectric signal is a few mu V.

Using a serial bilayer model we show that heterogeneous ferroelectric systems may exhibit substantial Maxwell-Wagner piezoelectric relaxation. The relaxation has its origin in the coupling of the dielectric and piezoelectric properties. The model predicts both retardation (positive phase angle and counterclockwise charge-pressure hysteresis) and relaxation (negative phase angle and clockwise charge-pressure hysteresis) of the longitudinal direct piezoelectric coefficient. The theoretical results are confirm

PLZT x/65/35 (x = 4, 8, 10) thin films were prepared by the acetic-acid based chemical solution deposition processing from lead tetraacetate, lanthanum nitrate and zirconium and titanium propoxides. Introducing top layer of PLZT with large PbO excess can prevent surface pyrochlore phase formation. It is further shown that although lead is depleted from PLZT because of the reaction with the substrate, perovskite phase is retained as a consequence of a large lead-oxide content throughout the film.

The transverse piezoelectric coefficient d(31)*, has been calculated for the six domain-engineered structures occurring in perovskite single crystals, using data for rhombohedral PMN-33PT [0.67Pb(Mg1/3Nb2/3)O-3-0.33PbTiO(3)], orthorhombic potassium niobate ...

Nava Setter

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Temperature dependence of piezoelectric properties for relaxor-ferroelectric solid solutions undergoing a rhombohedral to tetragonal phase transition

Dielectric and Structural Characteristics of Ba-Based and Sr-Based Complex Perovskites as a Function of Tolerance Factor

Structure and Energy of Charged Domain Walls in Ferroelectrics

Piezoelectric anisotropy: Enhanced piezoelectric response along nonpolar directions in perovskite crystals

Quantum properties of charged ferroelectric domain walls

What is a ferroelectric-a materials designer perspective

Polarization Switching and Domain Wall Motion in Circular and Ring Capacitor Structures in PZT Thin Films

Tunable ferroelectric thin films with enhanced responses through nano- structural control

Large enhancement of the piezoelectric response in perovskite crystals by electric bias field antiparallel to polarization

Pyroelectric thin-film sensor array

Magnetic domain wall propagation under ferroelectric control

Formation of charged ferroelectric domain walls with controlled periodicity

Micromachined PZT thin film actuators for micromotors

Antiferrodistortive Structural Phase Transition in Compressively-Strained Epitaxial SrTiO3 Film Grown on (La, Sr)(Al, Ta)O-3 Substrate

Preface: Science of ferroelectric thin films and application to devices

Erratum: Evidence for dielectric aging due to progressive 180° domain wall pinning in polydomain Pb(Zr0.45Ti0.55)O3 thin films [Phys. Rev. B 79, 054104 (2009)]

Processing and properties of thin film pyroelectric devices

Maxwell-Wagner piezoelectric relaxation in ferroelectric heterostructures

Influence of processing parameters on characteristics of sol-gel derived PLZT thin films

Domain engineering of the transverse piezoelectric coefficient in perovskite ferroelectrics