P. Wawrzała

Charge-Discharge Properties of PLZT x/90/10 Ceramics

This paper presents the results of investigations of the ceramic samples of perovskite type solid solution (Pb1-xLax)(Zr1-yTiy)O3 (PLZT—with x = 0.02, 0.03, 0.06 and 0.10, y = 0.9). Ceramic samples have been obtained from oxides using classical ceramic technology. The main aim of this paper is to compare the energy storage densities calculated from the P-E loops (at frequency of 1Hz) obtained as a result of integrating the area enclosed by E-P curve for tree types of ceramics—ferroelectric (PLZT with x = 0.02), slim-loop antiferroelectric (PLZT with x = 0.6, 0.10) and normal antiferroelectric with double loops (PLZT with x = 0.03).

Dielectric and electromechanical behaviors of PMN-PT ceramic samples

The results of the investigations on (1 — x)PMN-xPT ceramic samples obtained by sol—gel (SG) technology are presented in this study. In the (1 — x)PMN-xPT samples, the temperature Tm (at which real part of dielectric permittivity reaches its maximum) increases from ~270 K for x = 0 to ~500 K for x = 0.5. At room temperature, the samples with low values of x exhibit relaxor properties, while with increasing x the transition to normal ferroelectric properties takes place. Usually 0.9PMN-0.1PT or 0.925PMN-0.075PT solid solutions are considered as boundary compositions between relaxor and ferroelectric properties at room temperature.This study presents the analysis of X-ray diffraction patterns, fracture microphotographs, electromechanical parameters, and hysteresis loops for ceramics obtained from SG PMN—PT powders densified by the hot pressing method with a composition range, x = 0—0.37.

Technology and Properties of (1-x)PZT-(x)PFW Ceramics with 0.25<x<0.55

We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0.53Ti0.47O3)-x (PbFe2/3W1/3O3) [i.e. (1-x)PZT-xPFW] with x = 0.25, 0.35, 0.45 and 0.55 obtained from oxides using conventional ceramic technology. In this paper we present the results of investigations of XRD and main dielectric properties. For x = 0.25 and x = 0.35 we investigated also P-E hysteresis loops at room temperature.

Multiferroic Ceramic Composites Based on PZT Type Ceramic and NiZnFe Ferrite

Multiferroic (ferroelectric–ferromagnetic) ceramic composites were obtained on the basis of a ceramic powder of PZT type, i.e. Pb(Zr0.51Ti0.49)O3 + 0.2% at. Bi2O3 + 0.03% at. Nb2O5 + 0.06% at. MnO2 (marked as PZTBNM) and Pb0.84Ba0.16(Zr0.54Ti0.46)O3 + 1.0% at. Nb2O5 (marked as PBZTN). Admixtured compositions constituted of a PZT type ferroelectric powder with nickel-zinc ferrite (Ni1-xZnxFe2O4) as the magnetic content in the composite. Synthesis of the composite content was performed using compact sintering in the solid phase, while densification of the synthesized powder was achieved using the pressure-less sintering method (conventional sintering method). For the obtained multiferroic ceramic composites XRD investigations were performed, as well as investigations of microstructure, EDS, dielectric and magnetic properties, impedance and electrical hysteresis loop. The tests showed the existence of a correlation between magnetic and electric subsystems in the composites. Thanks to the ferroelectric and magnetic properties of the composites obtained, materials of this type could be applied, for example, in new memory types or magnetoelectric transducers.

Dielectric Properties of Pb0.75Ba0.25(Zr0.65Ti0.35)1-zSnzO3 Ceramics

In this work, the ceramics with the general formula of Pb0.75Ba0.25(Zr0.65Ti0.35)1-zSnzO3 (PBZST) for a constant x = 0.25, constant y = 0.35 and variable z = 0, 0.02, 0.04, 0.06, 0.08, 0.10 were obtained and examined. Powders synthesis was carried out using calcination method in conditions of: Tcalc = 850°C/tcalc = 3 h, and densification using free sintering method in conditions of: Ts = 1250°C/ts = 4h. For the obtained samples of PBZT and PBZTS ceramics, the microstructure and basic dielectric properties in the frequency function tests were performed. The PBZTS ceramics with relaxor properties is an interesting material to use in the modern electrical engineering, for instance as electrostriction transducers, sensors, or pulse capacitors.

Analysis of Hysteretic Behavior in a PBZTS Ceramics by a Preisach Distribution

This paper presents a new way of using the classical Preisach distribution to the analytical description of the behavior of ceramic ferroelectrics in a wide range of temperatures. The iteration method have been used to investigate the Preisach distribution from polarization-electric field hysteresis loops to observe the composition and temperature variation of the some parameters in lead barium zirconate titanate stannate ceramic samples. Received Preisach distributions from P-E hysteresis loops were modeled by selected analytical functions to find useful parameters to observing the evolution of the hysteresis loops with temperature. This type of analysis can allow a more complete understanding of the relaxor properties occurring in these kind of materials, and may be used to examination the changes of temperature changes of piezoelectric sensors.

Diffused AFE/RFE/PE phase transitions in (Pb0.88Ba0.1La0.02)(Zr0.6Sn0.4− x Ti x )0.995O3 ceramics obtained from oxides and carbonates

We present the results of preparation and investigation of antiferroelectric/relaxor/paraelectric (AFE/RFE/PE) phase transitions in ceramics, (Pb0.88Ba0.1La0.02)(Zr0.6Sn0.4− x Ti x )0.995O3 with x = 0.05, 0.055, 0.06, and 0.065, obtained from oxides and carbonates using a conventional ceramic technology. Such compositions can be good candidates for energy storage in pulse capacitors. For such application, the critical field should be appropriate, i.e., neither too high nor too low, since the transition from AFE to FE/RFE properties should take place in fields close to electric breakdown, since in such situation the stored energy is the biggest. We present the results of investigations of the microstructure, dielectric permittivity, and P–E hysteresis loops at various temperatures. It has been stated that some of the investigated materials exhibit field-induced AFE/FE or AFE/RF transition appropriate for application in pulse capacitors.

PLZT type ceramics as a material for applications in power pulse capacitors

This paper presents the results of investigations of the ceramic samples of perovskite type solid solution (Pb1-xLax) (Zr1-yTiy)O3 (PLZT - with x = 0.02, 0.03, 0.06 and 0.10, y = 0,9). Ceramic samples have been obtained from oxides using classical ceramic technology. The investigations results of microstructure, XRD, dielectric permittivity, P-E hysteresis loops and pulse discharge current-time measurements are presented in this work. The main aim of this paper is to compare the energy storage densities calculated from the P-E loops (at frequency of 1Hz) obtained as a result of integrating the area enclosed by E-P curve for tree types of ceramics - ferroelectric (PLZT with x = 0.02), slim-loop antiferroelectric (PLZT with x = 0.6, 0.10) and normal antiferroelectric with double loops (PLZT with x = 0.03). The results obtained in such a way have been compared with the energy storage densities obtained from capacitor discharge currents measurements. It has been stated that these compositions based on PLZT ceramics are the prospective materials for pulse power capacitors since they exhibit rather high values of electric breakdown field and relatively high values of dielectric permittivity.

Ferroelectric-ferromagnetic composites based on PZT type ceramic and NiZnFe ferrite

In the work, the ferroelectric-ferromagnetic composites were obtained on the basis of a ferroelectric powder of PZT type. Admixtured compositions of PZT type powders constituted ferroelectric, ferroelectric powder (90% of amount), whereas nickel-zinc ferrite (Ni1-xZnxFe2O4) was the magnetic content in the composite (10% of amount). Synthesizing the composite content was performed using compact sintering in the solid phase, while densification of the synthesized composite powder using the conventional sintering method. X-ray, tests, as well as microstructure, dielectric, magnetic and electric hysteresis loop tests were carried out. The tests showed existence of correlation between a magnetic and electric subsystems in the ferroelectric-ferromagnetic composites. Thanks to ferroelectric and magnetic properties of the composites obtained, materials of such type may be applied in new memory types.

Ceramics PMN-PT-PFN for Multilayer Capacitors

We present the technology of the solid solution with formula (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPb(Fe1/2Nb1/2)O3 where x=0.25, y=0.1 i.e. 0.9(0.75PMN-0.25PT)-0.1PFN. The addition of PFN decreases the temperature of final sintering and as a result such composition is interesting material for multilayer ceramic capacitors (MLCC). The powder of 0.9(0.75PMN-0.25PT)-0.1PFN has been obtained in three steps. In first step we obtained MgNb2O6. In second step FeNbO4 was obtained. In final third step the 0.9(0.75PMN-0.25PT)-0.1PFN was obtained from mixed powders MgNb2O6, FeNbO4 and PbO and TiO2. For obtained ceramics the following investigations have been made: XRD patterns, microstructure, EDS and main dielectric properties v.s. temperature. It has been stated that obtained ceramic powder is a good material for obtaining MLCC