Publications de Dragan Damjanovic

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Losses in piezoelectrics are approached by considering a description of direct stress-charge displacement hysteresis. Shortcomings of the usual loss models (viscous and Rayleigh, taken separately) are briefly demonstrated. Then, a mixed model for piezoelectric losses superimposing viscous and Rayleigh types of descriptions is proposed and validated for a modified lead titanate and lead zirconate titanate (PZT). It is shown for PZT that viscous and Rayleigh-like loss contributions can be effectively separate

Stress induced ferroelastic switching may represent an efficient toughening mechanism in piezoelectric-ferroelectric ceramics. During the crack propagation, the high tensional stresses at the crack tip can be partially released by the reorientation of 90 degree domains from along to perpendicular to the propagation direction. Compared to the phase transformation approach (inclusion of zirconia particles in the metastable tetragonal phase) this mechanism is not expected to reduce the piezoelectric properties

Using the Landau-Ginzburg-Devonshire approach, the longitudinal piezoelectric coefficient in an arbitrary direction, d(33)()(theta), was calculated as a function of temperature in tetragonal BaTiO3 crystals. The direction along which d(33)()(theta) is maximum is a function of piezoelectric d(ij) coefficients referred to the crystallographic coordinate system. Below a critical ratio of the shear and longitudinal coefficients, d(15)/d(33), the maximum d(33)(*)(theta) lies along the [001] axis. As the low-te

The longitudinal d(33) piezoelectric coefficient was studied in rhombohedral Pb(Zr0.6Ti0.4)O-3 thin films with (111), (100), and "random" orientation. The largest d(33) was found in (100)-oriented films and the smallest along the polarization direction in (111)-oriented films. These results are in a good qualitative agreement with recent theoretical predictions [Du, Zheng, Belegundu, and Uchino, Appl. Phys. Lett. 72, 2421 (1998)]. The field dependence of d(33) was also investigated as a function of crystall

A study was conducted on the effects of microstructure, atmosphere, and several dopants on the electrical conductivity of bismuth titanate (Bi4Ti3O12, BIT), Increased grain size increased the conductivity in undoped BIT as did acceptor dopants that substituted for either Bi (Ca and Sr) or Ti (Fe), A donor dopant (Nb) decreased the conductivity in BIT by as much as 3 orders of magnitude, The increased resistivity of Nb-doped BIT improved the polarization in an electric field, A piezoelectric coefficient, d(3

Modified lead titanate of the base composition (Pb,Ca)Ti-(Co,W)O3 + 0.01 mol % MnO was doped with 2 to 6 mol % strontium and barium to increase the dielectric constant, K, while preserving a high piezoelectric anisotropy (d33/d31). K was increased above 500 and a d33/d31 ratio of 34/1 was achieved when the composition Pb0.65Ca0.31Sr0.04Ti0.94-(Co0.5W0.5)0.06O3 + 0.01 mol% MnO was fabricated. The large d33/d31 resulted in an impressive hydrostatic piezoelectric coefficient (d(h) = 81 X 10(-12) m2/V). The rel

The Preisach approach was used to describe the widely observed quadratic field dependence of the direct longitudinal piezoelectric coefficient and its associated hysteresis loop. In this perspective, a four parameters distribution function was put forward and refined experimentally using bias stress variations. It permitted one to fully describe the stress bias dependence of the nonlinear coefficients. Considering the hysteresis loop associated with the proposed distribution function, modeling of the experi

The polarization and strain response of ferroelectric materials at electric fields below the macroscopic coercive field is of paramount importance for the operation of many electronic devices. The response of real ferroelectric and related materials is, in ...

In this study, ceramic samples of lead zirconate titanate Pb(Zr0.42Ti0.58)O3 (PZT 42/58) doped with Fe (hard) and Nb (soft) were studied by Raman, infrared (IR) and THz spectroscopy in the temperature range from 900 to 20 K. From the evaluation of the IR a ...

The high Curie temperature (T-C similar to 825 degrees C) of BiFeO3 has made this material potentially attractive for the development of high-T-C piezoelectric ceramics. Despite significant advances in the search of new BiFeO3-based compositions, the piezo ...

An environmentally friendly analog of the prominent methylammonium lead halide perovskite, methylammonium bismuth bromide (MA3Bi2Br9), was prepared and investigated in the form of powder, single crystals and nanowires. Complete characterization via synchro ...

Pure perovskite Pb(Sc1/2Nb1/2)O-3 thin films without pyrochlore phase were prepared by the sol-gel method on TiO2/Pt/TiO2/SiO2/Si substrates. Films exhibited (111) preferred orientation and columnar microstructure. Diffuse phase transitions with permittivity maximum decreasing in value and shifting toward higher temperature with increasing frequency and slim polarization-electric field hysteresis loops typical for relaxors were observed. The maximum field-induced piezoelectric d(33) coefficient measured wit

Pb(Mg1/3Nb2/3)O-3 (PMN) alkoxide precursor solutions were synthesized and used to prepare thin layers on TiO2/Pt/TiO2/SiO2/Si substrates by spin coating. Many parameters like homogeneity of the solution and appropriate processing must be controlled to minimize the pyrochlore formation. Optimization of the processing allowed highly (111)-oriented thin films to be obtained. Dielectric measurements and TEM investigations were performed and showed that PMN thin films exhibit relaxer behavior.

The longitudinal piezoelectric coefficient d(33) measured by the quasistatic (Berlincourt-type) method is strongly dependent on the sample aspect ratio (thickness/lateral dimension) and the type of contacts used to collect the charge and apply the pressure ...

The position of (Fe-Zr',(Ti)-V-O(center dot center dot))(center dot) defect complexes in Pb[Zr0.52Ti0.48]O-3 (PZT) piezoelectric ceramics was investigated by means of electron paramagnetic resonance (EPR) spectroscopy. The method of analysis pursued to obtain information on the (Fe-Zr',(Ti)-V-O(center dot center dot))(center dot) position is to compare the EPR spectra of Fe3+-doped PZT specimen at different states, i.e., a powder that is representative for a system with considerably reduced amount of non-18

Mobile charged defects, accumulated in the domain-wall region to screen polarization charges, have been proposed as the origin of the electrical conductivity at domain walls in ferroelectric materials. Despite theoretical and experimental efforts, this sce ...

We report on the experimental investigation of a high-frequency (1 MHz-1.8 GHz) dielectric dispersion in unpoled and poled Pb(Zr,Ti)O-3 ceramics. Two overlapping loss peaks could be revealed in the dielectric spectrum. The linear dependence between the low ...

The large piezoelectric effect of ferroelectric ceramics is utilized in many devices for sensing and actuating purposes. In this paper, the longitudinal direct piezoelectric effect in ceramics based on lead zirconate titanate, lead titanate, barium titanate and bismuth titanate is investigated as a function of the amplitude and frequency of the external pressure, the crystal structure and microstructure of the ceramics. The domain-wall contribution to the piezoelectric response appears to be a dominant extr

A micro-pump for medical applications is being developed using organometallic derived PZT thin films and silicon micromachining technology. Critical issues include the deposition of 'thick' PZT films (1 to 2 mu m thickness), film processing compatibility with available Si/SixNy/Ta/Pt structures and the establishing of piezoelectric poling parameters. A processing technique for the preparation of thick PZT films is presented. Piezoelectric properties are characterized by both direct method using alternating

A study was conducted on the effects of compositional modifications on the temperature coefficient of resonance frequency (TCF) in the disc planar vibration mode for the bismuth layer-structured compound SrBi2Nb2O9 (SBN)-based ceramics. The substitution of the strontium site by divalent and trivalent ions improved the TCF, accompanying the relaxation of elastic anomaly. The tolerance factor, t, was calculated for a pseudo cubic block to study the contribution of the structural factor to Curie temperature, T

Dragan Damjanovic

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Piezoelectric hysteresis analysis and loss separation

PFM investigation of stress induced ferroelastic switching in piezoelectric bulk ceramics

Crystal orientation dependence of the piezoelectric d(33) coefficient in tetragonal BaTiO3 as a function of temperature

Piezoelectric properties of rhombohedral Pb(Zr, Ti)O-3 thin films with (100), (111), and "random" crystallographic orientation

Microstructure, electrical conductivity, and piezoelectric properties of bismuth titanate

Modified Lead Calcium Titanate Ceramics with a Relatively Large Dielectric-Constant for Hydrophone Applications

Preisach distribution function approach to piezoelectric nonlinearity and hysteresis

Dielectric and electro-mechanic nonlinearities in perovskite oxide ferroelectrics, relaxors, and relaxor ferroelectrics

Lattice dynamics and dielectric response of undoped, soft and hard PbZr0.42Ti0.58O3

Piezoelectric response of BiFeO3 ceramics at elevated temperatures

Fast Lead-Free Humidity Sensor Based on Hybrid Halide Perovskite

Dielectric and piezoelectric properties of relaxor Pb(Sc1/2Nb1/2)O-3 thin films

Preparation and electromechanical properties of Pb(Mg1/3Nb2/3)O-3 thin film

Analytical modeling of the apparent d(33) piezoelectric coefficient determined by the direct quasistatic method for different boundary conditions

Position of defects with respect to domain walls in Fe[sup 3+]-doped Pb[Zr[sub 0.52]Ti[sub 0.48]]O[sub 3] piezoelectric ceramics

Domain-wall conduction in ferroelectric BiFeO3 controlled by accumulation of charged defects

Separation of piezoelectric grain resonance and domain wall dispersion in Pb(Zr,Ti)O-3 ceramics

Instabilities in the piezoelectric properties of ferroelectric ceramics

PZT films for micro-pumps

Properties of the elastic anomaly in SrBi2Nb2O9-based ceramics