Modified Lead Zirconate Titanate Research Articles

Nanoscale Structure–Property Relations in Sm Modified Lead Zirconate Titanate

Nanocrystalline ferroelectric Pb0.92Sm0.08(Zr0.53Ti0.47)0.98O3 with high dielectric constant has been synthesized by mechanical alloying (high energy ball milling). The ferroelectric material exhibits novel behavior when its crystallite size falls below a critical length scale of 40 nm. We observed phenomena such as significant decrease in dielectric constant and phase transition from Tetragonal to Cubic structure on reduction in crystallite size below 40 nm.

Grain growth kinetics and electrical properties of lanthanum modified lead zirconate titanate (9/65/35) based ferroelectric ceramics

The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd3+ doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth law was observed for samples with grain size varying from 1.00 up to 2.35 μm. The porosity and grain size dependences of the phase transition parameters, such as the maximum dielectric permittivity and its corresponding temperature (εm and Tm, respectively) were also investigated. The ac conductivity analyses followed the universal Jonscher law. The behavior of the frequency exponent (s) was analyzed through the correlated barrier hopping model. Both ac and dc conductivity results have been correlated with the observed microstructural features.

Ionized oxygen vacancy-related electrical conductivity in (Pb1−xLax)(Zr0.90Ti0.10)1−x/4O3 ceramics

The electrical conductivity behaviour in the paraelectric state has been investigated in lanthanum modified lead zirconate titanate (PLZT) ceramics, considering the universal relaxation law. The contribution of conductive processes to the dielectric response for the low-frequency range was discussed taking into account the oxygen vacancies mechanism. The activation energies for the thermally hopping and conductivity processes were obtained. The results for the frequency dependence of the conductivity suggest at the oxygen vacancy hopping processes, due to relaxations in oxygen vacancy-related dipoles, being mainly responsible for the conduction behaviour in the studied system.

Modeling the dielectric response of lanthanum modified lead zirconate titanate ferroelectricceramics—an approach to the phase transitions in relaxor ferroelectrics

The relaxor behavior of lanthanum modified lead zirconate titanate (PLZT) ferroelectric ceramics, for aLa/Zr/Ti ratioof x/60/40, has been analyzed. An approximation to the dynamical behavior of the polar nano-regions(PNRs) has been discussed, taking into account a relaxation model, which considers adistribution function for the relaxation times. A good agreement between theoretical andexperimental results was obtained. The behaviors of the mean relaxation time and itsstandard deviation with temperature were discussed, considering the correlation betweenthe polar nano-regions and the freezing temperature. The temperature dependence of thepolarization showed an anomalous behavior around a temperature, which was associatedwith the freezing temperature, according to the proposed model in the present work.

Effects of lanthanum modification on dielectric properties of Pb(Zr0.90,Ti0.10)O3 ceramics: enhanced antiferroelectric stability

Lanthanum modified lead zirconate titanate ceramics with lanthanum content changing from 2 to 6 at% La and a Zr/Ti ratio of 90/10 (PLZT x/90/10) have been analyzed by using X-ray diffraction, dielectric response, differential scanning calorimetry, and ferroelectric hysteresis. An antiferroelectric state was found to be stabilized, whereas the long-range ferroelectric state was disrupted by lanthanum substitution on the lead sites. A ferroelectric state is shown to be stable over an antiferroelectric state for low lanthanum contents in a wide temperature range, where both phases coexist. With the increase of the lanthanum concentration, the long-range coherency of the ferroelectric state is suppressed, i.e., the temperature range of the ferroelectric state stability decreased, disappearing for x > 3 at% La.

The effects of the post annealing temperatures of (Pb 0.92La 0.08)(Zr 0.65Ti 0.35)O 3 (PLZT) thin films on ITO coated glass

Lanthanum modified lead zirconate titanate thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrate by R.F. magnetron sputtering method. The thin films were deposited at 500 °C and annealed at various temperatures (550 ~ 750 °C) by rapid thermal processing. The structure and the morphology of the films were measured by an X-ray diffraction and an atomic force microscope. The hysteresis loops and the fatigue properties of thin films were measured by a precision material analyzer. As the annealing temperature increased, the remnant polarization value increased whereas the coercive field was reduced. In our switching polarization endurance analysis, the remnant polarization of PLZT thin films annealed at 750 °C decreased after 10 9 switching cycles in the form of square waves.

Phase Transition via Intermediate State and Control of Piezoelectric Parameters

The influence of the electric field on the stability of phases in antiferroelectric substance with a small difference in energies of the ferroelectric and antiferroelectric states is studied. Theoretical prediction that the interaction between the coexisting domains of the ferroelectric and antiferroelectric phases provides the stability of the nonuniform intermediate state of the substance in external electric field is confirmed experimentally. The composition-electric field phase diagrams with intermediate state are obtained for the lanthanum modified lead zirconate-titanate based solid solutions. Variation of piezoelectric properties of these solid solutions during the phase transition via intermediate state is studied. It is shown that the effective control of piezoelectric parameters by external electric field is possible in materials with such phase transition.

Optical properties study of PLZT films deposited on sapphire Substrate

Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on sapphire ( 0001) substrate by sol–gel method. The cell parameters of films were calculated with help of whole-pattern fitting procedure. The evolution of strain, shift of absorption edge and change in the band tailing with film thickness were found and analyzed for amorphous and polycrystalline PLZT films. The refractive index n was computed with help of “Envelope method” and dielectric function was calculated by fitting the measured optical transmission spectrum.

Structural and electrical properties of Sm3+ substituted PZT ceramics

Abstract Samarium modified lead zirconate titanate (PSZT: Pb 1− x Sm x (Zr 0.65 Ti 0.35 )O 3 : x = 0, 0.02, 0.04, 0.06) ceramics were synthesized by solid state ceramic route. XRD shows single-phase formation with rhombohedral structure up to x = 0.04. With Sm—substitution, the grain size first increases up to x = 0.02 and then decreases. A metal/ferroelectric/metal (MFM) structure was made by depositing gold electrode on the flat surfaces for electrical measurements. All samples show normal ferroelectric behaviour, however, a squareness of P–E loop (polarization vs. electric field) was observed to increase with Sm content. Higher electromechanical coupling coefficients ( K p and K t ) have been achieved for the PZT with 6 mol% Sm substitution and having fine grain size.

The influence of ferroelectric KTN particles on electric properties of 0–3 ferroelectric composites

A triphasic ferroelectric composite is obtained when ferroelectric potassium tantalate niobate particles [KTN] with a high dielectric constant and electric conductivity are embedded in a traditional 0–3 manganese and niobate modified lead zirconate titanate [PMNZT]/polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] copolymer biphasic-ferroelectric composite. The electric properties are studied for the ferroelectric composite in which the volume fraction of KTN particles is in the range 0%–24% and KTN is a passive phase. The experimental data show that the volume fraction of KTN particles strongly influence the electric properties of ferroelectric composite, and that the triphasic composite doped with KTN has higher ferroelectric, piezoelectric and pyroelectric properties than the biphasic composite with the same PMNZT volume fraction.

ITO 기판에 제작된 PLZT 박막의 후열처리 온도에 따른 전기적 특성평가

R.F 마그네트론 스퍼터링 방법을 이용하여 Indium tin oxide(ITO)가 증착된 유리기판 위에 PLZT (<TEX>$Pb_{1.1}La_{0.08}Zr_{0.65}Ti_{0.35}O_3$</TEX>) 박막을 제작하였다. 기판온도를 <TEX>$500^{\circ}C$</TEX>로 고정하여 증착한 후 급속열처리 방법으로 다양한 온도 (<TEX>$550-750^{\circ}C$</TEX>)에서 후열처리 하였다. 후열처리온도의 변화에 따른 PLZT 박막의 결정학적 특성을 X선 회절법을 통하여 분석하였고 원자간력 현미경을 이용하여 박막의 표면 상태를 관찰하였다. 또한 precision material analyzer 을 이용하여 분극이력곡선과 피로특성을 측정하였다. 후 열처리 온도가 증가함에 따라 잔류분극 값(Pr)은 <TEX>$10.6{\mu}C/cm^2$</TEX> 에서 <TEX>$31.4{\mu}C/cm^2$</TEX>로 증가하였으며 항전계(Ec)는 79.9 kV/cm에서 60.9 kV/cm로 감소하는 경향을 보였다. 또한 피로특성의 경우 1MHz 주파수에서 <TEX>${\pm}5V$</TEX>의 square wave를 인가하여 측정한 결과 <TEX>$700^{\circ}C$</TEX>에서 후열처리한 시편의 경우 <TEX>$10^9$</TEX>회 이상의 분극반전을 거듭하였을 때 분극값이 15% 감소하는 결과를 나타내었다. Lanthanum modified lead zirconate titanate (<TEX>$Pb_{1.1}La_{0.08}Zr_{0.65}Ti_{0.35}O_3$</TEX>) thin films were fabricated on indium doped tin oxide (ITO)-coated glass substrate by R.F magnetron sputtering method. The thin films were deposited at <TEX>$500^{\circ}C$</TEX> and post-annealed with various temperature (<TEX>$550-750^{\circ}C$</TEX>) by rapid thermal annealing technique. The structure and morphology of the films were characterized with X-ray diffraction (XRD) and atomic force microscopy (AFM) respectively. The hysteresis loops and fatigue properties of thin films were measured by precision material analyzer. As the annealing temperature was increased, the remnant polarization value was increased from <TEX>$10.6{\mu}C/cm^2$</TEX> to <TEX>$31.4{\mu}C/cm^2$</TEX>, and coercive field was reduced from 79.9 kV/cm to 60.9 kV/cm. As a result of polarization endurance analysis, the remnant polarization of PLZT thin films annealed at <TEX>$700^{\circ}C$</TEX> was decreased 15% after <TEX>$10^9$</TEX> switching cycles using 1MHz square wave form at <TEX>${\pm}5V$</TEX>.

The Electrical Properties of PLZT Thin Films on ITO Coated Glass with Various Post-Annealing Temperature

Lanthanum modified lead zirconate titanate (Pb1.1La0.08Zr0.65Ti0.35O3) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrate by r.f magnetron sputtering method. The thin films were deposited at 500°C and annealed at various temperature (550~600°C) by rapid thermal processing. The structure and morphology of the films were characterized with X-ray diffraction and atomic force microscopy. The hysteresis loops and fatigue properties of thin films were measured by precision material analyzer. As the annealing temperature increased, the remnant polarization value increased from 10.58 DC/cm2 to 31.35 DC/cm2, coercive field was reduced from 79.906 kV/cm to 60.937 kV/cm. For the switching polarization endurance analysis, the remnant polarization of PLZT thin films annealed at 700°C was decreased 15% after 109 switching cycles using 1MHz square wave form at 5V.

Band Gap and Band Tailing Behaviour of PLZT Films

Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on sapphire (0001) substrate by sol-gel method. The cell parameters of films were calculated with help of whole pattern fitting procedure. The study of optical properties revealed the fractal behaviour of absorption coefficient near the absorption edge. The strong shift of the absorption edge in thin films in comparison with bulk PLZT was observed. This shift could not be caused just by the presence of the strain. The increased disorder and polarization fluctuations were suggested as the additional reason that was supported by nearly twice higher value of the exponential tail width in the films in comparison with bulk PLZT.

Influence of graphite particle size on electrical properties of modified PZT–polymer composites

Abstract Piezoceramics–polymer composites using modified lead zirconate titanate (Pb 0.88 Sr 0.12 Zr 0.54 Ti 0.44 Sb 0.02 O 3 ) and polyethylene (PE) were prepared by a calendaring method. The modified ceramic powder was prepared by a conventional solid-state method. Graphite powder of various particle sizes was also added into the composites. Properties of the composites as a function of particle sizes of the ceramics and graphite were studied. The relative permittivity and piezoelectric coefficient (d 33 ) of the composites were found to increase with increasing the particle size of the modified ceramics. Composites contained finer graphite particle also found to give higher d 33 values.

Phase Transition Characters in Tin Modified Lead Zirconate Titanate Compounds

Antiferroelectric materials of double electric hysteresis could be used to large displacement actuator, discharge capacitor and transducer. Phase transition characters induced with electric field and temperature were studied in lager tin modified lead zirconate titanate compounds Pb 0.99 Nb 0.02 [(Zr 0.60 Sn 0.40 ) 1 − x Ti x ] 0.98 O 3 . Antiferroelectric composition range of double hysteresis was measured at x ≤ 0.064. Differing from lower tin modified PZST the permittivity formed a hathpace at high temperature region in Pb 0.99 Nb 0.02 [(Zr 0.60 Sn 0.40 ) 1 − x Ti x ] 0.98 O 3 family. This dielectric hathpace was caused by a transitional paraelectric phase which depressed the sharp Curie peak. Dielectric hathpace became higher and narrower as x component increasing.

Development of perovskite and phase transition in lead cobalt niobate modified lead zirconate titanate system

Abstract Ferroelectric lead zirconate titanate–lead cobalt niobate ceramics with the formula (1 − x )Pb(Zr 1/2 Ti 1/2 )O 3 – x Pb(Co 1/3 Nb 2/3 )O 3 where x = 0.0–0.5 were fabricated using a high temperature solid-state reaction method. The formation process, the structure and homogeneity of the obtained powders have been investigated by X-ray diffraction method as well as the simultaneous thermal analysis of both differential thermal analysis (DTA) and thermogravimetry analysis (TGA). It was observed that for the binary system (1 − x )Pb(Zr 1/2 Ti 1/2 )O 3 – x Pb(Co 1/3 Nb 2/3 )O 3 , the change in the calcination temperature is approximately linear with respect to the PCoN content in the range x = 0.0–0.5. In addition, X-ray diffraction indicated a phase transformation from a tetragonal to a pseudo-cubic phase when the fraction of PCoN was increased. The dielectric permittivity is remarkably increased by increasing PCoN concentration. The maximum value of remnant polarization P r (25.3 μC/cm 2 ) was obtained for the 0.5PZT–0.5PCoN ceramic.

Epitaxial Growth and Electrical Characterization of PBZT Thin Films by RF Magnetron Sputtering Deposition

Barium modified lead zirconate titanate (PBZT) thin films were grown epitaxially on Pt/Ti/SiO2/Si substrates by radio-frequency magnetron sputtering deposition and characterized by X-ray diffraction and scanning electron microscopy. Depending on the growth condition, a wide variation of crystal structure and morphology was evolved in PBZT thin films. The formation of phase structure and pyrochlore phase was strongly dependent on the oxygen partial pressure and re-evaporation of lead from the films during the deposition. Perovskite films were obtained by optimizing the deposition conditions and analyzed by the ferroelectric hysteresis (P~E).

Dielectric and Piezoelectric Properties of Praseodymium Modified Lead Zirconate Titanate Ceramics

Praseodymium (Pr) modified lead zirconate titanate ceramics (Pb1-1.5xPrx (ZryTi1-y) O3 with x = 0.02, 0.04, 0.06, 0.08 and y = 0.51, 0.52, 0.54, 0.56, 0.58, 0.60) were prepared by the high temperature solid-state reaction method. X-ray diffraction (XRD) results show that the morphotropic phase boundary (MPB) of Pb0.955Pr0.03(ZryTi1-y)O3 (PPZT1) is located in the area where the molar fraction of Zr is near 55%, when the molar fraction of Zr is 54% and the sintering temperature is 1240°C with 1h curing time, the superior piezoelectric properties of compositions of PPZT1 system were optimized, a set of d33 = 420 pC/N; eT 33/e0 = 2,000; Tc = 314°C; Qm = 76; tand = 2% and kp = 0.53. On the other hand, Pb1-1.5xPrx(Zr0.54Ti0.46)O3 (PPZT2) is far from MPB and their compositions are all in tetragonal phase.

Preparation and optical characterization of lanthanum modified lead zirconate titanate thin films on indium-doped tin oxide-coated glass substrate

Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrate by sol–gel method. The structure of the films was characterized with X-ray diffraction and scanning electron microscopy. The optical properties were investigated in the wavelength range of 220–2400 nm. The sample was modelled as a three layer structure on finite substrate, and optical constants of this system were calculated from the transmission and reflection spectra. The calculated dielectric function was fitted with the Drude model in the case of ITO and a sum of Lorentzian oscillators in the case of PLZT films. For PLZT film the anomalous behaviour of imaginary part of dielectric function was observed below the absorption edge. The possible reasons of that behaviour were discussed.

Impedance spectroscopy study of strontium modified lead zirconate titanate ceramics

( Pb 0.97 Sr 0.03 ) ( Zr 0.05 Ti 0.95 ) O 3 nanocrystalline powder was prepared by a solution based chemical method. Preliminary x-ray diffractogram analysis of some aspects of crystal structure showed that a single-phase compound was formed exhibiting a tetragonal system. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the material, which is also evident from the scanning electron microscope micrographs. The bulk conductivity indicates an Arrhenius-type thermally activated process. The ac conductivity spectrum obeyed the Jonscher power law. Modulus analysis indicated the possibility of hopping mechanism for electrical processes in the system with a nonexponential type of conductivity relaxation.