Showing papers on "Ferroelectric ceramics published in 2002"
TL;DR: In this article, a general form for multiaxial constitutive laws for ferroelectric ceramics is constructed, where switching surfaces and associated flow rules are postulated in a modified stress and electric field space such that a positive dissipation rate during switching is guaranteed.
Abstract: In this paper, a general form for multi-axial constitutive laws for ferroelectric ceramics is constructed. The foundation of the theory is an assumed form for the Helmholtz free energy of the material. Switching surfaces and associated flow rules are postulated in a modified stress and electric field space such that a positive dissipation rate during switching is guaranteed. The resulting tangent moduli relating increments of stress and electric field to increments of strain and electric displacement are symmetric since changes in the linear elastic, dielectric and piezoelectric properties of the material are included in the switching surface. Finally, parameters of the model are determined for two uncoupled cases, namely non-remanent straining ferroelectrics and purely ferroelastic switching, and then for the fully coupled ferroelectric case.
247 citations
TL;DR: In this paper, a very high apparent dielectric constant peak with frequency dispersion was observed, and attributed to the Maxwell-Wagner polarization model in dielectrics.
Abstract: Dense ceramic composites consisting of two phases, ferroelectric BaTiO3 and ferrite (Ni0.3Zn0.7)Fe2.1O4, were synthesized via the solid state reaction route. The results indicate that insulating BaTiO3 can be well compatible to the conductive phase (Ni0.3Zn0.7)Fe2.1O4. The electrical conduction and dielectric behavior of the materials vary with the ratio of the two phases. The dielectric behavior is greatly influenced by the conductive phase. At x=0.3, a very high apparent dielectric constant peak with frequency dispersion was observed, and attributed to Maxwell–Wagner polarization. The application of the Maxwell–Wagner polarization model in dielectric materials is briefly discussed.
238 citations
TL;DR: In this article, the dielectric relaxation rate of Ba(Ti0.7Zr0.3)O3 ceramics was studied in the temperature range from 150 to 450 K.
Abstract: Ferroelectric-relaxor behavior of Ba(Ti0.7Zr0.3)O3 ceramics is studied in the temperature range from 150 to 450 K. A broad dielectric peak with a high-dielectric maximum exhibits frequency dispersion. The dielectric relaxation rate follows the Vogel–Fulcher relation with E=0.21 eV and TVF=199.6 K. The polarization hysteresis loops were observed with a remnant polarization of 10 μC/cm2 at 175 K. The high-dielectric constant and high-polarization properties are expected to find practical applications at low temperatures.
236 citations
TL;DR: In this article, the effects of MgO mixing with BST on BST phase transitions were examined, and it was observed that Mg substitution into BST causes a shift in the cubic-tetragonal BST phase transition peak to a lower temperature.
Abstract: The dielectric properties of Ba0.6Sr0.4TiO3 (BST) and 1.0, 20.0, 40.0, and 60.0 wt % MgO-mixed BST bulk ceramics and thin films were investigated for tunable microwave applications. The effects of MgO mixing with BST on BST phase transitions were examined. It is observed that Mg substitution into BST causes a shift in the cubic-tetragonal BST phase transition peak to a lower temperature. Mg-substituted BST and MgO-mixed phases exhibit depressed and broadened BST phase transition peaks, resulting in decreased dielectric constants and dielectric losses at room temperature. BST and 1.0, 20.0, 40.0, and 60.0 wt % MgO-mixed BST thin films (∼0.3 μm thick) were deposited on (100) MgO single-crystal substrates at 750°C in an oxygen ambient pressure of 200 mTorr by pulsed laser deposition. The MgO–BST composite thin films showed a relatively high dielectric Q (=1/tan δ) compared to the pure BST and Mg-substituted BST thin films while retaining useful dielectric tuning.
201 citations
TL;DR: The temperature and thickness dependence of permittivity of (Ba,Sr)TiO3 has been investigated in this paper, where films were deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO2/Si, with thicknesses ranging from 15 to 580 nm.
Abstract: The temperature and thickness dependence of permittivity of (Ba,Sr)TiO3 has been investigated. The films were deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO2/Si, with thicknesses ranging from 15 to 580 nm. The dielectric response was measured from 100 to 520 K. As film thickness decreased, the maximum dielectric constant decreased, the temperature at which the maximum dielectric constant occurred decreased, and the peak in the dielectric constant became more diffuse. A model incorporating a thickness independent interior and a nonferroelectric surface cannot account for these thickness dependencies. To appropriately model these observations a physical model containing thickness and temperature dependent interior and surface components is necessary.
197 citations
TL;DR: In this article, a phenomenological constitutive law for ferroelectric switching due to multi-axial mechanical and electrical loading of a polycrystalline material is developed, which is based on kinematic hardening plasticity theory and has a switching surface in the space of mechanical stress and electric field.
179 citations
TL;DR: In this paper, single ferroelectric lead titanate (PTO) grains down to 15 nm were fabricated by chemical solution deposition and the grain-size-dependent domain configuration was studied using three-dimensional piezoresponse force microscopy (PFM).
Abstract: Single ferroelectric lead titanate (PTO) grains down to 15 nm were fabricated by chemical solution deposition. Varying the dilution of the precursor solution leads to different grain sizes between 15 and 200 nm. The grain-size-dependent domain configuration was studied using three-dimensional piezoresponse force microscopy (PFM). It is found that the PTO grains in a dense film contain laminar 90° domain walls, whereas separated PTO grains show more complicated structures of mainly 180° domain walls. For grains smaller than 20 nm, no piezoresponse was observed and we suppose this could be due to the transition from the ferroelectric to the superparaelectric phase which has no spontaneous polarization. Recent calculations showed that the ferroelectricity of fine ferroelectric particles decrease with decreasing particle size. From these experiments the extrapolated critical size of PTO particles was found to be around 4–14 nm.
162 citations
TL;DR: In this paper, the effect of dc electric field on the dielectric properties of Ba(Ti0.7Zr0.3)O3 ceramics with an obvious ferroelectric-relaxor behavior (Tm∼229 K, 10 kHz) is reported.
Abstract: The effect of dc electric field (E) on the dielectric properties of Ba(Ti0.7Zr0.3)O3 ceramics with an obvious ferroelectric-relaxor behavior (Tm∼229 K, 10 kHz) is reported. The dielectric constant is greatly suppressed and a low loss is obtained under dc electric fields (⩽40 kV/cm). The low loss (tan δ∼0.002) and high tunability (∼45%) were obtained for the Ba(Ti0.7Zr0.3)O3 ceramics around 300 K, indicating that it is a promising candidate for tunable materials at room temperature. The field dependence of the temperature (Tm) of the dielectric constant maximum follows the ΔTm∼E2/3 relation, indicating a second-order phase-transition-like behavior.
159 citations
TL;DR: In this article, the integration of epitaxial ferroelectric Pb(Zr, Ti)O3 (PZT) thin films on Si [100] substrates using a SrTiO3 template layer and a conducting perovskite (La 0.5Sr0.5)CoO3 electrode was reported.
Abstract: In this letter, we report on the integration of epitaxial ferroelectric Pb(Zr, Ti)O3 (PZT) thin films on Si [100] substrates using a SrTiO3 (STO) template layer and a conducting perovskite (La0.5Sr0.5)CoO3 electrode. X-ray diffraction studies reveal both in-plane and out-of-plane alignment of the heterostructure. The epitaxial films show extremely high remnant polarization as well as piezoelectric d33 coefficients compared to textured and untextured polycrystalline films.
134 citations
TL;DR: In this paper, the effect of electric field induced Fm3m M R3m phase transition and high long range ordering of B ions in the ABO 3 perovskite structure was investigated in ferroelectric ceramics.
Abstract: Electrocaloric effect (ECE) of pure and modified PbSc 1/2 Ta 1/2 O 3 (PST) and its solid solutions and PbMg 1/3 Nb 2/3 O 3 - PbTiO 3 ferroelectric ceramics is studied at different temperatures and external electric field intensities. High value of (ECE) up to 2.3 K is observed in PST ceramics at modification in B sublattice by Co 3+ and Sb 5+ ions. The features of ECE in PST are explained by significant structure rearrangement at electric field induced Fm3m M R3m phase transition and high long range ordering of B ions in the ABO 3 perovskite structure. A further increase of ECE is observed in ceramic multilayer capacitors at higher electric field intensities up to 138 kV/cm.
132 citations
TL;DR: In this paper, a high dielectric constant polymer composite system was presented, which used a high-dielectric-constant cyanoresin polymer filled with ferroelectric ceramics, such as BaTiO 3 powder.
Abstract: A high dielectric constant polymer composite system is presented. The new composite uses a high dielectric constant cyanoresin polymer filled with ferroelectric ceramics, such as BaTiO 3 powder. While dielectric constant of the polymer is 21 at 1 kHz, the dielectric constant of the composite is over 130 at the BaTiO 3 volume fraction of 51%, which is the highest dielectric constant reported so far for the polymer composite materials based on BaTiO 3 filler. Frequency and temperature dependence of the dielectric constant of the composites are reported.
TL;DR: In this paper, the out-of-plane piezoelectric response (d33) measured via piezoresponse scanning force microscopy, of submicron capacitors fabricated from epitaxial PbZrxTi1−xO3 thin films was investigated.
Abstract: We report on the out-of-plane piezoelectric response (d33), measured via piezoresponse scanning force microscopy, of submicron capacitors fabricated from epitaxial PbZrxTi1−xO3 thin films. Investigations on 1 μm2 and smaller capacitors show that the substrate-induced constraint is dramatically reduced by nanostructuring. At zero field, the experimentally measured values of d33 for clamped as well as submicron capacitors are in good agreement with the predictions from thermodynamic theory. The theory also describes very well the field dependence of the piezoresponse of clamped capacitors of key compositions on the tetragonal side of the PbZrxTi1−xO3 phase diagram as well as the behavior of submicron PbZr0.2Ti0.8O3 (hard ferroelectric) capacitors. However, the field-dependent piezoresponse of submicron capacitors in compositions closer to the morphotropic phase boundary (soft ferroelectrics) is different from the behavior predicted by the theoretical calculations.
TL;DR: In this paper, the dielectric permittivity of A-site ion substituted (Na1/2Bi 1/2)TiO3(A=Pb,Sr) solid solutions has been investigated with the aid of structural analysis.
Abstract: The dielectric permittivity of A-site ion substituted (Na1/2Bi1/2)TiO3(A=Pb,Sr) solid solutions has been investigated with the aid of structural analysis. As the addition of PT increased, the first order characteristics of the phase transition appeared. In contrast, additions of ST made the solid solution exhibit relaxor ferroelectrics behavior. Microscopic structural analysis revealed that the dielectric properties were determined by cation ordering which controlled the translational symmetry and domain configuration. In the NBT–PT solid solution, A-site cations were randomly redistributed and macrodomains formed. However, the addition of ST distributed A-site cations with local ordering and divided the domains of NBT into micropolar regions. The contrasting effects of the addition of the Pb and Sr cations on the dielectric properties of NBT are discussed in terms of the polarizability and the tolerance factors as they relate to the perovskite structure.
TL;DR: In this article, experimental results interrelating the different scales of the fatigue mechanism showing that all forms of fatigue occur in ferroelectric ceramics are visible as etch grooves in strongly etched surfaces by scanning electron microscopy.
Abstract: Fatigue in ferroelectric ceramics is the result of an intricate interplay of electrical, mechanical and electrochemical processes, each of which has been claimed responsible for fatigue. We present experimental results interrelating the different scales of the fatigue mechanism showing that all forms of fatigue occur. Electrochemical mechanisms lead to point defect agglomeration. The agglomerates are rendered visible as etch grooves in strongly etched surfaces by scanning electron microscopy. The overall length of the etch grooves strongly increases during cycling. Micro- and macrocracking were both observed and quantified using electron and optical microscopy. Their number similarly increases as a result of fatigue. Furthermore, a shrinkage of the unit cell volume was found by XRD.
TL;DR: In this paper, the dielectric and ferroelectric properties of tungsten bronze Sr2−xCaxNaNb5O15 (SCNN, x=0.05-0.35) ceramics were investigated.
Abstract: This letter reports the dielectric and ferroelectric properties of tungsten bronze Sr2−xCaxNaNb5O15 (SCNN, x=0.05–0.35) ceramics. Two dielectric anomalies and a diffuse ferroelectric transition behavior were appreciably observed in the compositions of x=0.05–0.25. The incorporation of smaller calcium cations into the crystal structure resulted in an increase in the Curie temperature, from 279 (x=0.05) to 297 (x=0.35), and a decrease in the permittivity, from 1353 to 543, at their respective Curie temperatures. Ferroelectricity was observed in the compositions with x=0.05–0.25, but absent in the compositions with x=0.30 and 0.35 at room temperature. The maximum spontaneous polarization Ps of 9.1 μC/cm2 and remanent polarization Pr of 3.0 μC/cm2 were achieved in the composition of x=0.15.
TL;DR: In this article, the influence of grain boundaries on the dielectric properties of ferroelectric ceramics and polycrystalline thin films is described theoretically by the method of effective medium.
Abstract: The influence of grain boundaries on the dielectric properties of ferroelectric ceramics and polycrystalline thin films is described theoretically by the method of effective medium. Grain boundaries are modeled by low-permittivity (“dead”) layers, which do not exhibit ferroelectric instability. The effective permittivity of a polycrystalline material is calculated in the paraelectric regime above the transition temperature. The calculations are based on the solution of electrostatic problem for a spherical dielectric inclusion separated from the surrounding dissimilar matrix by a low-permittivity interface layer. For isotropic bulk ceramics, an analytic expression is derived for the effective permittivity as a function of the grain size, dead-layer thickness, and its permittivity. Temperature dependence of the aggregate dielectric response is calculated for BaTiO3 (BT) ceramics of different grain sizes and found to be in good agreement with measurements. It is shown that grain boundaries not only renormalize the Curie-Weiss temperature and constant, but may also cause deviations from the Curie-Weiss law. For BT polycrystalline thin films grown on dissimilar substrates, numerical calculations of the effective dielectric constants are performed, taking into account both the grain-boundary and substrate effects on the film anisotropic dielectric response. Theoretical predictions are compared with the grain size dependence of the permittivity of BT films grown on Pt-coated Si.
TL;DR: In this article, the phase transformation temperature Tp corresponds to the peak in the e(T) obtained from the temperature dependence of dielectric constant, and Tp and Tm exhibit thermal hysteresis.
Abstract: Ferroelectric phase transformation characteristics of ceramic BaTiO3 have been studied by combined thermo-Raman and dielectric measurements. The temperature dependence of Raman bands at 311 and 721 cm−1 shows that tetragonal to cubic (T–C) phase transformation occurs over a range of temperature. The increase in the bandwidths of these bands indicates that this transformation is an order-disorder transformation. The differential thermo-Raman intensity thermograms show a dip at a temperature corresponding to the maximum rate of phase transformation and this temperature can be defined as phase transformation temperature Tp. The ferroelectric transformation temperature Tm corresponding to the peak in the e(T) obtained from the temperature dependence of dielectric constant is found to coincide with Tp. This indicates that maximum in dielectric constant occurs at the maximum rate of T–C phase transformation. Both Tp and Tm exhibit thermal hysteresis. The Curie temperature TC obtained from the intersection of ta...
TL;DR: In this article, a second order paraelectric-ferroelectric transition in the films was suggested at a thickness of ∼500 nm, which was confirmed by dielectric measurements.
Abstract: Pulsed-laser deposition has been used to fabricate Au/Ba0.5Sr0.5TiO3/SrRuO3/MgO thin film capacitor structures. Crystallographic and microstructural investigations indicated that the Ba0.5Sr0.5TiO3 (BST) had grown epitaxially onto the SrRuO3 lower electrode, inducing in-plane compressive and out-of-plane tensile strain in the BST. The magnitude of strain developed increased systematically as film thickness decreased. At room temperature this composition of BST is paraelectric in bulk. However, polarization measurements suggested that strain had stabilized the ferroelectric state, and that the decrease in film thickness caused an increase in remanent polarization. An increase in the paraelectric–ferroelectric transition temperature upon a decrease in thickness was confirmed by dielectric measurements. Polarization loops were fitted to Landau–Ginzburg–Devonshire (LGD) polynomial expansion, from which a second order paraelectric–ferroelectric transition in the films was suggested at a thickness of ∼500 nm. F...
TL;DR: In this article, the electric permittivity of the sodium niobate ceramic was investigated in the temperature range from 15 up to 900 K, at frequencies from 100 Hz to 1 MHz.
Abstract: The electric permittivity of the sodium niobate ceramic was investigated in the temperature range from 15 up to 900 K, at frequencies from 100 Hz to 1 MHz. Three anomalies were found in the permittivity curve. A phase transition for NaNbO3 was assigned to anomaly at around 280 K, while other two ones have previously been reported. In addition, the dielectric permittivity dependence with the temperature and frequency, at temperatures lower than 400 K, showed two regions with typical characteristics of a relaxor ferroelectric materials.
TL;DR: In this paper, structural and physical properties of ferroelectric and ferrimagnetic pulsed-laser deposition-grown thin-film BaFexTi1−xO3 with 0.5⩽x ⩽0.75 (BFTO) are compared with those of BaTiO3 (BTO) films deposited under identical conditions.
Abstract: Structural and physical properties of ferroelectric and ferrimagnetic pulsed-laser deposition-grown thin-film BaFexTi1−xO3 with 0.5⩽x⩽0.75 (BFTO) are compared with those of BaTiO3 (BTO) films deposited under identical conditions. Fe leads to lattice expansion and deterioration of the crystalline quality in the as-prepared films. Signatures of the paraelectric–ferroelectric phase transition in lattice parameters, resistivity, and capacitance tend to be suppressed in BTO films, but are clearly distinguished in the presence of Fe. While strain elevates TC above bulk values in thin-film BTO to ∼200 °C, Fe doping entails further increases of TC up to ∼320 °C. Current versus voltage measurements demonstrate that Fe converts n-type BTO into p-type BFTO. Fe doping brings about ferrimagnetic ordering with a Neel temperature above 450 °C.
TL;DR: In this paper, a finite element algorithm is developed using the virtual work principle to simulate the rate dependence in the polarization and strain responses to applied alternating electric field of different frequencies in qualitative consistence with experimental observations.
TL;DR: In this paper, the authors performed fatigue tests on lead zirconate titanate (PZT) multilayers having stacks of Pb(Zr0.8Ti0.2)O3/Pb(N 0.2Ti 0.8) O3 with repeated distances of 12 formula groups and concluded that fatigue is dominated by space-charge layers.
Abstract: We have performed fatigue tests on lead zirconate titanate (PZT) multilayers having stacks of Pb(Zr0.8Ti0.2)O3/Pb(Zr0.2Ti0.8)O3 with repeated distances of 12 formula groups. The results are compared with single-layer n-type (0.5 at. % Ta-doped) PZT films. We conclude that fatigue is dominated by space-charge layers in each case, but that in the multilayer such space charge accumulates at the layer interfaces, rather than at the electrode–dielectric interface. The model, which includes both drift and diffusion, is quantitative and yields a rate-limiting mobility of 6.9±0.9×10−12 cm2/V s, in excellent agreement with the oxygen vacancy mobility for perovskite oxides obtained from Zafar et al.
TL;DR: In this paper, the dielectric spectra of Ca1−xPbxTiO3 solid solutions were studied at frequencies between 10 Hz and 1 MHz in a temperature range of 4.2-300 K with transformation to a relaxor type behavior at x>0.3.
Abstract: Dielectric spectra of ceramic samples of Ca1−xPbxTiO3 (0⩽x⩽0.4) solid solutions were studied at frequencies between 10 Hz and 1 MHz in a temperature range of 4.2–300 K. A ferroelectric phase transition was observed at x=0.3 with transformation to a relaxor type behavior at x>0.3. The transition temperature Tc follows a linear dependence Tc∝(x−xc) with xc=0.28 contrary to a square-root dependence Tc∝(x−xc)1/2 predicted by the theory for incipient ferroelectrics. The critical concentration essentially exceeds the xc values for SrTiO3 and KTaO3 incipient ferroelectrics.
TL;DR: In this paper, the ferroelectric and piezoelectric properties of (001) BiScO3-PbTiO3 epitaxial films were investigated.
Abstract: The ferroelectric and piezoelectric properties of (001) BiScO3–PbTiO3 epitaxial films were investigated. Epitaxial films 1 μm thick were grown by pulsed laser deposition using ceramic targets of (1−x)BiScO3–xPbTiO3 (x=0.5) at substrate temperatures of 700 °C on (100) SrRuO3/(100)LaAlO3 substrates. Well-saturated hysteresis loops with a remanent polarization of 36 μC/cm2 were observed. The films had a room temperature dielectric constant of 800, tan δ=0.09 and a maximum permittivity of 3600 at 460 °C. The room temperature e31f piezoelectric coefficient was −9 C/m2. The piezoelectric properties obtained were comparable to those of Pb(Zr,Ti)O3 or relaxor ferroelectric-PbTiO3 films.
TL;DR: In this article, the authors have shown that NKN thin films can be grown on LaAlO3 substrates by rf magnetron sputtering of a stoichiometric, high-density, ceramic target.
Abstract: Epitaxial Na0.5K0.5NbO3 (NKN) thin films have been grown on LaAlO3 substrates by rf magnetron sputtering of a stoichiometric, high-density, ceramic target. X-ray diffraction analysis showed c-axis oriented cube-on-cube growth. Micrometer size interdigital capacitor (IDC) structures were defined on the surface of the NKN film using photolithography. The electrical characterization at 1 MHz showed dissipation factor tan δ of 0.010, tunability 16.5% at 200 kV/cm and dielectric permittivity er=470. The frequency dispersion of er between 1 kHz and 1 MHz was 8.5% and the IDCs showed very good insulating properties with leakage current density on the order of 30 nA/cm2 at 400 kV/cm. The polarization loop exhibits weak ferroelectric hysteresis with maximum polarization 23.5 μC/cm2 at 600 kV/cm. These results are promising for tunable microwave devices based on rf sputtered NKN thin films.
TL;DR: In this paper, the effects of grain orientation on electrical properties such as dielectric, ferroelectric, piezoelectric and pyroelectric properties of some grain-oriented BLSF ceramics by the hotforged (HF) method, comparing them with ordinarily fired (OF) non-oriented ones.
Abstract: The grain orientation technique, which is one of several ceramic preparation methods with a controlled grain structure during the ceramic sintering process, gives an anisotropic single-crystal-like behavior to the ceramics with lower symmetric crystal structure such as the bismuth layer-structured and the tungsten bronze types than the perovskite structure. Bismuth layer-structured ferroelectrics (BLSF) are characterized by low dielectric constant, high Curie temperature and large anisotropy in electromechanical coupling factors than those of PZT family. Further more, the characteristics can be easily enhanced by the grain orientation. This paper describes the effects of grain orientation on electrical properties such as dielectric, ferroelectric, piezoelectric and pyroelectric properties of some grain-oriented BLSF ceramics by the hotforged (HF) method, comparing them with ordinarily fired (OF) non-oriented ones.
TL;DR: In this paper, the phase structure and dielectric properties of relaxor-type ferroelectric ceramics were investigated and a region with both pseudocubic and tetragonal phase in existence lies in the composition range x=0.34-0.38, which is the morphotropic phase boundary (MPB).
TL;DR: In this article, an ion beam etch of sputtered Pb(Zrx,Ti1−x)O3 (PZT) with x equal to 0.54 thin films grown on Pt/Ti/SiO2/Si substrates has been performed using pure Ar gas.
Abstract: Ion beam etching of sputtered Pb(Zrx,Ti1−x)O3 (PZT) with x equal to 0.54 thin films grown on Pt/Ti/SiO2/Si substrates has been performed using pure Ar gas. The etch rate dependence on the process parameters (current density, acceleration voltage, gas pressure) has been investigated. The PZT etch rate can reach 600 A/min with acceleration voltage of 1000 V and current density of 1 mA/cm2. Selectivity ratios between PZT and masks of various natures (photoresist, Pt, Ti) have been evaluated to determine a pertinent material for etching mask. According to our etching conditions, titanium seems to be the best candidate. We evaluated the PZT surface damage by contact mode atomic force microscopy. It appears that the roughness increases after ion bombardment, and that the grain boundary zone is preferentially etched. For some etching parameters, we also observed electrical damage. Carrying out C(V) and hysteresis loops P(E) measurements before and after etching have provided evidence of degradation. We noted a large decrease in permittivity after the etching process irrespective of the current density and acceleration voltage. Ferroelectric damage was illustrated by a large increase in the average coercive field. For each of the electrical properties under study, the same behavior has been observed after etching: the increase of damage was obtained as a function of the current density and acceleration voltage. The evolution of electrical properties when the PZT layer is protected by a metallic mask has also been studied. We observed very slight variations in the electrical properties.
TL;DR: In this article, a review of recent developments in processing, properties and applications of composite and multilayer ferroelectric thin films is presented, with selected examples from recent literature and the origin of enhancement.
Abstract: This paper reviews recent developments in processing, properties and applications of composite and multilayer ferroelectric thin films. Methods such as physical vapor deposition, chemical vapor deposition and sol-gel, for the processing of composite and multilayer ferroelectric films are described. Among the techniques reviewed for the fabrication of multilayer ferroelectric films, molecular beam epitaxy and atomic layer metal-organic chemical vapor deposition are the most suitable techniques for the deposition of superlattices with atomically sharp interface. As an efficient and quick way, pulsed-laser deposition has been widely used for the preparation of ferroelectric multilayers and heterostructures. Superior dielectric properties have been reported for sol-gel-derived micrometer-thick ceramic/ceramic composite ferroelectric films. Properties of multilayer ferroelectric films vary as a function of periodicity, which can be exploited for the development of various electronic devices. Enhanced characteristics of composite and multilayer films with selected examples from recent literature and the origin of enhancement are discussed and summarized. Finally, applications of the materials for the development of various electronic devices are also presented.
TL;DR: In this article, the pyroelectric properties of MnO2 doped compositions in the Pb(Mg1/3Nb2/3)O3-PbTiO3/PbZrO3 system have been investigated for an uncooled pyro electric infrared detecting application, looking primarily at compositions in Pb ZrO 3-rich corner of the phase diagram.
Abstract: The pyroelectric properties of MnO2 doped compositions in the Pb(Mg1/3Nb2/3)O3–PbTiO3–PbZrO3 system have been investigated for an uncooled pyroelectric infrared detecting application, looking primarily at compositions in the PbZrO3-rich corner of the phase diagram. A processing route from the metal oxides through to the poled ceramic has been developed, which has reduced the size and frequency of defects in the sintered ceramic necessary for producing thin ( � 200 mm) ceramic wafers. The electrical properties relevant to the pyroelectric application (dielectric constant, tand and pyroelectric coefficient) have been surveyed with respect to composition to produce the best values of the pyroelectric ‘figure of merit’ FD ¼ p/{c 0 (""otan� ) 1/2 } at room temperature. The effects of compositional changes in the ceramic on the two phase transitions from: the ferroelectric low temperature to ferroelectric high temperature phases (FR(LT) to FR(HT)) and the ferroelectric high temperature to paraelectric phases at the Curie point have also been investigated. The consequential changes of the electrical properties are reported. The resisitivity of the ceramic proved insensitive to either the amounts of excess lead or manganese doping levels. # 2002 Elsevier Science Ltd. All rights reserved.