Publications de Dragan Damjanovic

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Introducing symmetry breaking in materials enables the emergence of functionalities. This can be microscopically and macroscopically driven by applying external stimuli such as mechanical stress, electric field, temperature, and chemical modification. For instance, non‐zero net dipole moments are formed in a material with the presence of local charged defects or their clusters, which can alter the crystal structure, charge states, and electrostatic potential across the material. Here, a conceptual approach

We report on the frequency and stress dependence of the direct piezoelectric d33 coefficient in BiFeO3 ceramics. The measurements reveal considerable piezoelectric nonlinearity, i.e., dependence of d33 on the amplitude of the dynamic stress. The nonlinear ...

Oxygen octahedra tilting is a common structural phenomenon in perovskites and has been subject of intensive studies, particularly in rhombohedral Pb(Zr,Ti)O3 (PZT). Early reports suggest that the tilted octahedra may strongly affect the domain switching be ...

Piezoelectric ZnO coatings on optical fibers are of interest for active optical-fiber devices such as phase and wavelength modulators. Reactive magnetron sputtering has been used to prepare high-resistivity [001] radially oriented ZnO coatings on 85 mm long sections of Cr/Au-coated optical fibers. The impedance spectra of 2 and 6 mm long transducers are analyzed between 1 kHz and 100 MHz by applying an electrical potential across the thickness of the ZnO coating. The capacitance of these devices exhibits a

The piezoelectric effect in ferroelectric single crystals and ceramics is investigated considering intrinsic (lattice), and extrinsic (originating mainly from displacement of domain walls) contributions. The focus of the study of intrinsic properties is on ...

Relaxor Pb(Sc1/2Nb1/2)O-3 (PSN) thin films without pyrochlore phase were processed from the modified alkoxide solution precursors. The preparation of single phase PSN thin films has a narrow processing window due to the appearance of an undesirable pyrochlore phase and volatility of PbO. Thin film processing has been improved through selection of precursor solutions, heat treatment and optimized deposition-condition are optimized. Especially, the effects of Pt substrates seeded with additional layers upper

It is shown that at weak alternating stress the relationship between the piezoelectrically induced charge and applied stress in ferroelectric ceramics has the same form as the Rayleigh law for magnetization versus magnetic field in ferromagnetic materials. Applicability of the Rayleigh law to the piezoelectric effect is demonstrated in detail for lead zirconate titanate (PZT) ceramics. Experimental results indicate that the dominant mechanism responsible for piezoelectric hysteresis and the dependence of th

Direct measurements of longitudinal (d(33)) and transverse (d(31)) piezoelectric coefficients have been made on cuboid samples of 001-poled 0.955Pb[Zn1/3Nb2/3]O-3-0.045PbTiO(3) (PZN-4.5PT) and 0.68Pb[Mg1/3Nb2/3]O-3-0.32PbTiO(3) (PMN-32PT) single crystals. The measurements were made in a Berlincourt-type press over a wide range of dynamic and static bias stresses. In the transverse mode, the response was found to be essentially anhysteretic and d(31) was independent of the dynamic stress amplitude. In c

Bismuth-based layered compounds have been considered during the last years as interesting materials fur high temperature piezoelectric applications, due to their stability and wide thermal range of the ferroelectric activity. The high electrical conductivity present at high temperatures has been a disadvantage for the potential applications of these compounds. On Bi4Ti3O12 (BIT), different doping such as Nb5+ and W6+ were used to increase resistivity. It has been shown that Nb5+ doping modifies piezoelectri

Lead-free (1 - y)(Bi1/2Na1/2TiO3-xBi(1/2)K(1/2)TiO(3))-yK(0.5)Na(0.5)NbO(3) [(1 - y)(BNT-xBKT)-yKNN] (0.1

The influence of annealing between the Curie transition and the melting point of solvent cast polyvinylidene fluoride trifluoroethylene copolymer films on the crystalline structure, mechanical and electrical properties, and oxygen permeability is investiga ...

The printing of lead zirconate titanate (PZT, Pb(Zr,Ti)O-3) piezoelectric thick films on silicon substrates is being studied for potential use as microactuators, microsensors, and micro.. transducers. A fundamental challenge in the fabrication of useful PZT thick-film devices on silicon is to sinter the PZT to high density at sufficiently low temperature to avoid mechanical or chemical degradation of the silicon substrate. The goal of the present study is to develop and implement suitable electrodes and PZT

The lead magnesium niobate [Pb(Mg1/3Nb2/3)O-3 or PMN], and its solid solutions with lead titanate (PbTiO3 or PT), are of great interest because of their high electromechanical properties. At large PMN content, these materials exhibit relaxor characteristics with large electrostrictive strains and a large permittivity, while compositions near the morphotropic phase boundary present very interesting piezoelectric properties. So far, properties of these materials in ceramic, thin film and single-crystal form h

The dielectric properties of undoped, Nb-, and Fe-doped Pb(Zr,Ti)O3 ceramics with composition near morphotropic phase boundary were investigated in the frequency range from 1 MHz to 20.2 GHz at room temperature. Temperature dependences of dielectric permittivity ε′ and loss ε″ are measured at 100 kHz from 50 to 300 K and around 13.4 GHz from 100 to 300 K. These measurements permit estimation of the upper limit of the intrinsic permittivity and lower limit of the extrinsic contributions to the permittivity a

The effect of silylation of microfibrillated cellulose (MFC) surfaces on β‐phase formation in poly(vinylidene difluoride) (PVDF) and the resulting viscoelastic and dielectric performance of MFC‐PVDF composites is investigated. Two different organosilanes, ...

Strain response of polycrystalline barium titanate (BaTiO3) was investigated under high unipolar electric field (0 to 4 kV/mm) and compressive stress (0 to 400 MPa) in the temperature range from 25 to 160 degrees C. In the vicinity of the Curie point (T-C), nonlinear and hysteretic strain-electric field and strain-stress constitutive behaviors were observed, persisting above T-C where they correspond to the well-known electric field induced double loop polarization behavior. Analogous to the electrical doub

The structural phase diagram of the Pb-free ferroelectric (Na1/2Bi1/2)1−xBaxTiO3, x

Large bipolar strain of up to 0.36% (peak-to-peak value) was measured in BiFeO3 ceramics at low frequency (0.1 Hz) and large amplitude (140 kV/cm) of the driving field. This strain is comparable to that achievable in highly efficient morphotropic phase bou ...

Aging of piezoelectric properties was investigated in lead-free (1 - x)(Bi1/2Na1/2)TiO3-xBaTiO(3) doped with 1at.% Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging p ...

Electric-field-induced phase transitions have been evidenced by macroscopic strain measurements at temperatures between 25 degrees C and 100 degrees C in 001-poled (1-x)Pb(Mg1/3Nb2/3)O-3-xPbTiO(3) [(PMN-xPT);x=0.25,0.305,0.31] and (1-x)Pb(Zn1/3Nb2/3)O ...

Dragan Damjanovic

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Tunable and Persistent Macroscopic Polarization in Nominally Centrosymmetric Defective Oxides

Piezoelectric nonlinearity and frequency dispersion of the direct piezoelectric response of BiFeO3 ceramics

Role of charged defects on the electrical and electromechanical properties of rhombohedral Pb(Zr,Ti)O3 with oxygen octahedra tilts

Electrical characterization of sputter-deposited ZnO coatings on optical fibers

Contributions to the piezoelectric effect in ferroelectric single crystals and ceramics

Sol-gel derived Pb(Sc0.5Nb0.5)O-3 thin films: Processing and dielctric properties

Stress and frequency dependence of the direct piezoelectric effect in ferroelectric ceramics

Direct piezoelectric effect in relaxor-ferroelectric single crystals

Study and control of the conductivity of Nb-doped Bi4Ti3O12 for high temperature piezoelectric applications

Effect of K0.5Na0.5NbO3 on properties at and off the morphotropic phase boundary in Bi1/2Na1/2TiO3-Bi1/2K1/2TiO3 ceramics

Process influences on the structure, piezoelectric, and gas-barrier properties of PVDF-TrFE copolymer

Processing and properties of screen-printed lead zirconate titanate piezoelectric thick films on electroded silicon

Pb(Mg1/3Nb2/3)O-3 and (1-x)Pb(Mg1/3Nb2/3)O-3-xPbTiO(3) relaxor ferroelectric thick films: Processing and electrical characterization

Domain wall contributions in Pb(Zr,Ti)O3 ceramics at morphotropic phase boundary: A study of dielectric dispersion

Surface modified microfibrillated cellulose‐poly(vinylidene fluoride) composites: β‐phase formation, viscoelastic and dielectric performance

Critical mechanical and electrical transition behavior of BaTiO3: The observation of mechanical double loop behavior

Structural complexity of (Na0.5Bi0.5)TiO3-BaTiO3 as revealed by Raman spectroscopy

Large Electric-Field Induced Strain in BiFeO3 Ceramics

Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi1/2Na1/2)TiO3-xBaTiO3 piezoelectric ceramics

Electric-field-, temperature-, and stress-induced phase transitions in relaxor ferroelectric single crystals