Showing papers on "Perovskite (structure) published in 2005"

Current status and prospects of lead-free piezoelectric ceramics

Abstract: Dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layer-structured ferroelectric (BLSF) ceramics are described as superior candidates for lead-free piezoelectric materials to reduce environmental damages. Perovskite type ceramics seem to be suitable for actuator and high power applications that are required a large piezoelectric constant, d 33 (>300 pC/N) and a high Curie temperature, T c (>200 °C). For BaTiO 3 (BT)-based solid solutions, that is, (1 − x )BaTiO 3 − x (Bi 0.5 K 0.5 )TiO 3 [BTBK − 100 x ] ceramics, the T c increases with increasing the amount of x . BTBK-20 + MnCO 3 0.1 wt.% ceramic shows the high T c than 200 °C and the electromechanical coupling factor, k 33 = 0.35. In the case of a (Bi 1/2 Na 1/2 )TiO 3 − b BaTiO 3 − c (Bi 1/2 K 1/2 )TiO 3 [BNBK (100 a /100 b /100 c )] solid solution ceramics, the d 33 and T c are 191 pC/N and 301 °C for the BNBK (85.2/2.8/12), respectively. On the other hand, BLSF ceramics seem to be excellent candidates as piezoelectric sensors for high temperatures and ceramic resonators with high mechanical quality factor ( Q m ), and low temperature coefficient of resonance frequency (TC- f r ). Donor-doped Bi 4 Ti 3 O 12 ceramics such as Bi 4 Ti 3− x Nb x O 12 [BITN- x ] and Bi 4 Ti 3− x V x O 12 [BITV- x ] show high T c than 650 °C. The k 33 value of the grain-oriented (HF) BITN-0.08 ceramic is 0.39 and is able to keep the same value up to 350 °C. Bi 3 TiTaO 9 (BTT)-based solid solution system, Sr x −1 Bi 4− x Ti 2− x Ta x O 9 [SBTT2( x )] (1 ≦ x ≦ 2), displays the high Q m value (=13500) in (p)-mode at the x = 1.25 composition.

Semiconductor memory device

Abstract: PROBLEM TO BE SOLVED: To enable mixed mounting with a highly efficient electrical body capacitative element and a highly efficient logic circuit, by forming a dielectrics capacitative element of perovskite structure at low temperature, as well as by suppressing characteristic fluctuation and characteristics degradation of an integrated circuit. SOLUTION: In Pb-based perovskite dielectrics capacitative element, a mixing layer is so constituted that Ru is diffused in an LaNiO 3 -based film in order to raise adhesiveness of an Ru-based layer to the interface of the LaNiO 3 -based film, using lower electrodes wherein perovskite type conductivity oxide LaNiO 3 and Ru which is noble metal are laminated, and moreover the orientation degree of Ru (002) is 90% or more, and LaNiO 3 has a preference orientation degree (100), so that the orientation and grain size of a PZT film are controlled. Thus, the PZT film excellent in flatness and orientation is obtained. COPYRIGHT: (C)2005,JPO&NCIPI

Superior Perovskite Oxide‐Ion Conductor; Strontium‐ and Magnesium‐Doped LaGaO3: I, Phase Relationships and Electrical Properties

Abstract: The single-phase, cubic-perovskite region of the LaO1.5-SrO-Gao1.5-MgO phase diagram was determined from room-temperature and high-temperature X-ray diffraction. Two impurity phases were identified, LaSrGaO4 and aSrGa3O7. The conductivity of the oxygen-deficient perovskite phase was shown to be essentially a purely oxide-ion conductivity sigmao over a wide range of oxygen partial pressures 10-22 lessthan equal to PO2 lessthan equal to 1 atm. The highest values of sigmao = 0.17 and 0.08 S/cm were found for La0.8Sr0.2Ga0.83Mg0.17O0.2815 at 800° and 700°C, respectively; they remain stable over a week-long test. The Arrhenius plot of sigmao is curved, dividing into a high-temperature region T > T* similar/congruent 600°C and a low-temperature region T < T*. Above T* all the oxygen vacancies appear to be mobile; below T* they progressively condense into clusters of ordered vacancies.

Tuning the Band Gap in Hybrid Tin Iodide Perovskite Semiconductors Using Structural Templating

Abstract: Structural distortions within the extensive family of organic/inorganic hybrid tin iodide perovskite semiconductors are correlated with their experimental exciton energies and calculated band gaps. The extent of the in- and out-of-plane angular distortion of the SnI42- perovskite sheets is largely determined by the relative charge density and steric requirements of the organic cations. Variation of the in-plane Sn−I−Sn bond angle was demonstrated to have the greatest impact on the tuning of the band gap, and the equatorial Sn−I bond distances have a significant secondary influence. Extended Huckel tight-binding band calculations are employed to decipher the crystal orbital origins of the structural effects that fine-tune the band structure. The calculations suggest that it may be possible to tune the band gap by as much as 1 eV using the templating influence of the organic cation.

Achieving fast oxygen diffusion in perovskites by cation ordering

Abstract: The oxygen-exchange behavior has been studied in half-doped manganese and cobalt perovskite oxides. We have found that the oxygen diffusivity in Gd0.5Ba0.5MnO3−δ can be enhanced by orders of magnitude by inducing crystallographic ordering among lanthanide and alkali-earth ions in the A-site sublattice. Transformation of a simple cubic perovskite, with randomly occupied A sites, into a layered crystal GdBaMn2O5+x (or isostructural GdBaCo2O5+x for cobalt oxide) with alternating lanthanide and alkali-earth planes reduces the oxygen bonding strength and provides disorder-free channels for ion motion, pointing to an efficient way to design new ionic conductors.

Effect of Ordering‐Induced Domain Boundaries on Low‐Loss Ba(Zn1/3Ta2/3)O3‐BaZrO3 Perovskite Microwave Dielectrics

Abstract: Small substitutions of BaZrO 3 into Ba[(Zn,Ni) 1/3 Ta 2/3 ]O 3 are utilized in the commercial preparation of low-loss perovskite microwave dielectrics. The structures of a series of these phases with substitution levels ranging from 1% to 5% BaZrO 3 were examined using high-resolution TEM. For < 2.15% BaZrO 3 the solid solutions retain the ordered 1:2 structure of the Ba[(Zn,Ni) 1/3 Ta 2/3 ]O 3 end-member but are comprised of small ordered domains whose size decreases as the Zr content is raised. The decrease in the size of the domains parallels a decrease in the processing time required to access a low-loss state. Although for pure Ba[(Zn,Ni) 1/3 Ta 2/3 ]O 3 reductions in the degree of cation order produce a large increase in the dielectric loss, the Zr-substituted ceramics retain a very low loss. We believe the low losses of the 1:2 ceramics are derived from the stabilization of the ordering-induced domain boundaries via the partial segregation of the Zr cations. For substitutions between 3% and 5% BaZrO 3 the size of the ordered domains continues to decrease but the system undergoes an abrupt transformation to a cubic 1:1 ordered structure with a doubled perovskite repeat. The structures of these phases have been interpreted using a random layer model in which one site is occupied by Ta and the other by a random distribution of Zn, Zr, and the remaining Ta cations, i.e., Ba{[Zn (2-y)/3 Ta (1-2y)/3 Zr y ] 1/2 [Ta 1/2 ]}O 3 . Although the ordering is confined to nano-sized domains, these ceramics also exhibit low losses, again reflecting the relative stability of the domain boundaries. In this case we believe the low losses reflect the effectiveness of the random layer in stabilizing the anti-phase boundaries.

Electron diffraction of tilted perovskites

Abstract: Simulations of electron diffraction patterns for each of the known perovskite tilt systems have been performed. The conditions for the appearance of superlattice reflections arising from rotations of the octahedra are modified to take into account the effects of different tilt systems for kinematical diffraction. The use of selected-area electron diffraction as a tool for perovskite structure determination is reviewed and examples are included.

Hydrogen Cycling of Niobium and Vanadium Catalyzed Nanostructured Magnesium

Abstract: The reaction of hydrogen gas with magnesium metal, which is important for hydrogen storage purposes, is enhanced significantly by the addition of catalysts such as Nb and V and by using nanostructured powders. In situ neutron diffraction on MgNb0.05 and MgV0.05 powders give a detailed insight on the magnesium and catalyst phases that exist during the various stages of hydrogen cycling. During the early stage of hydriding (and deuteriding), a MgH1

Electric modulus approach to the analysis of electric relaxation in highly conducting (Na 0.75 Bi 0.25 )(Mn 0.25 Nb 0.75 )O 3 ceramics

Abstract: Broadband dielectric spectroscopy is applied to investigate the electrical properties of disordered perovskite-like ceramics in a wide temperature range. From the x-ray diffraction analysis it was found that the newly obtained (Na0.75Bi0.25) (Mn0.25Nb0.75)O3 ceramics consist of two chemically different phases. The major perovskite one has an orthorhombic structure described by the Pbcm space group (No 57, in yxz setting). The minor phase shows an orthorhombic symmetry, all-face-centred lattice F, with the lattice parameters a = 10.797(4) A, b = 7.601(3) A and c = 7.691(3) A. The electric modulus M* formalism used in the analysis enabled us to distinguish and separate the relaxation processes, dominated by marked conductivity in the e*(ω) representation. In the ceramics studied, the relaxation times are thermally activated and the dipole process has a clearly non-Debye behaviour. The relaxation process described with the use of the activation energy of approximately 0.4 eV and the characteristic relaxation time, τ0 = 1 × 10−11 s, was found to be related to oxygen vacancies. The low frequency relaxation shows Debye behaviour with a slightly lower activation energy and a longer characteristic time.

Ferroelectric Na0.5Bi0.5TiO3 and K0.5Bi0.5TiO3 Perovskites and Their Solid Solutions

Abstract: Properties of the perovskite ferroelectrics Na0.5Bi0.5TiO3 (NBT), K0.5Bi0.5TiO3 (KBT) and their solid solutions are reviewed. Consideration of the NBT behavior draws attention to phenomena of the ion ordering, coexistence of several phase regions within a crystal lattice, phase transition diffusion and to a quite new phenomenon: existence of the isotropization points (temperatures) in the AFE-phase-temperature interval. In the KBT the isotropic points are absent. NBT, KBT, and their solid solutions are considered as possible useful materials for technical (in particular, for piezoelectric) applications. There are also some other A0.5 +Bi0.5B4+O3 perovskites which are interesting for future research.

Predicting morphotropic phase boundary locations and transition temperatures in Pb- and Bi-based perovskite solid solutions from crystal chemical data and first-principles calculations

Abstract: Using data obtained from first-principles calculations, we show that the position of the morphotropic phase boundary (MPB) and transition temperature at MPB in ferroelectric perovskite solutions can be predicted with quantitative accuracy from the properties of the constituent cations. We find that the mole fraction of PbTiO3 at MPB in Pb(B′B″)O3–PbTiO3, BiBO3–PbTiO3, and Bi(B′B″)O3–PbTiO3 exhibits a linear dependence on the ionic size (tolerance factor) and the ionic displacements of the B cations as found by density-functional-theory calculations. This dependence is due to competition between the local repulsion and A-cation displacement alignment interactions. Inclusion of first-principles displacement data also allows accurate prediction of transition temperatures at the MPB. The obtained structure-property correlations are used to predict morphotropic phase boundaries and transition temperatures in as yet unsynthesized solid solutions.

Crystal Structure and Diffusion Path in the Fast Lithium-Ion Conductor La0.62Li0.16TiO3

Abstract: We report the results of a neutron powder diffraction study of the La(0.62)Li(0.16)TiO3 perovskite that determined the diffusion path of lithium cations at room temperature. At 77 K, the Li cations are located at the 2c site (Wycoff notation of the Cmmm space group) on the (002) La deficient layer, while, at room temperature, they are spread over a wide area and migrate following the 2c-4f-2c or 2c-2d-2c tie line on the (002) layer. The probability density of Li cations has a minimum between the 2c and 4f or between the 2c and 2d positions on the diffusion path in contrast to the previous reports where the bottleneck has been thought to be located at the 2c, 2d, and 4f positions. On the basis of the present structural model, the Li-cation conductivity is discussed in terms of a two-dimensional bond-percolation model for Li-cation diffusion. It was found that the vacancy at the La site is essential for the Li-cation conduction.

Superior perovskite oxide-ion conductor; Strontium- and magnesium-doped LaGaO3 : III. Performance tests of single ceramic fuel cells

Abstract: The performance of La0.8Sr0.2Ga0.83Mg0.17O2.815 (LSGM) as an optimized electrolyte of a solid oxide fuel cell was tested on single cells having a 500-µm-thick electrolyte membrane. The reactivity of NiO and LSGM suggested use of an interlayer to prevent formation of LaNiO3. The interlayer Sm-CeO2 was selected and sandwiched between the electrolyte and anode. Comparison of Sm-CeO2/Sm-CeO2+ Ni and Sm-CeO2+ Ni as anodes showed that Sm-CeO2/Sm-CeO2+ Ni gave an exchange current density 4 times higher than that of Sm-CeO2+ Ni. The peak power density of the interlayered cell is 100 mW higher than that of the standard cell without the interlayer. This improvement is due to a significant reduction of the anode overpotential; the overpotential of the cathode La0.6Sr0.4CoO3-delta (LSCo) remained unchanged. Comparison of the peak power density in this study and with that of a previous study, also with a 500-µm-thick electrolyte, indicates a factor of 2 improvement, i.e., from 270 mW/cm2 to 550 mW/cm2 at 800°C. The excellent cell performance showed that an LSGM-based thick membrane SOFC operating at temperatures 600° < Top < 800°C is a realistic goal.

Dense Perovskite, La1-xA′xFe1-yCoyO3-δ (A′= Ba, Sr, Ca), Membrane Synthesis, Applications, and Characterization

Abstract: La1-xA′xFe0.8Co0.2O3-δ (A′= Ca, Sr, Ba) perovskite powders were synthesized to attain the desired properties of high O2 flux and stability under reducing conditions. Steady-state oxygen permeation rates for La1-xA′xFe0.8-Co0.2O3-δ perovskite membranes in nonreacting experiments with air on one side and helium on the other side of the membrane were in the order A′x= Ba0.8 > Ba0.6 > Ca0.6 > Sr0.6. Partial oxidation of methane to syngas (CO + H2) was performed in a dense La0.2Ba0.8Fe0.8Co0.2O3-δ membrane reactor at 850°C in which oxygen was separated from air and simultaneously fed into the methane stream. The reducing atmosphere affected the membrane reaction-side surface while barium enrichment occurred on the air-side surface. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.

Oxygen storage capacity of La1−xA′xBO3 perovskites (with A′ = Sr, Ce; B = Co, Mn)—relation with catalytic activity in the CH4 oxidation reaction

Abstract: The aim of this work was to study the effect of cation-substitution on the reducibility of the perovskite, as well as the effect on the catalytic activity for the CH 4 oxidation reaction. Six perovskites (LaCoO 3 , LaMnO 3 , La 1− x Sr x MnO 3 ( x = 0.2, 0.4), and La 1− x Ce x MnO 3 ( x = 0.05, 0.1)) were synthesized by reactive grinding. The reducibility of the perovskite was studied by means of the oxygen storage capacity (OSC) measurement. OSC was performed at different temperatures on LaCoO 3 and LaMnO 3 , in order to elucidate the different mechanisms of reduction involved at each temperature. The substituted samples showed that reduction profile is modified at high-substitution degrees; however, no differences were observed on the OSC values (amount of most active oxygen, calculated after one pulse of CO) between the pure lanthanum sample and the substituted ones. Tested in the CH 4 oxidation reaction, the LaCoO 3 sample was found to present a little higher activity than LaMnO 3 , even if the cobalt-based sample presented a smaller specific surface area. Moreover, all the substituted samples presented very slightly higher activities than the pure LaMnO 3 solid. Because of the supposed redox oxidation mechanism (Mars-Van-Krevelen), this agrees well with the OSC results obtained for the reducibility of the manganese on these samples, by which it was observed that substitution does not clearly affect the immediate reduction of the manganese.

Perovskite Hollow-Fiber Membranes for the Production of Oxygen-Enriched Air†

Abstract: Oxygen-enriched air with 30–50 vol%O2 is used in a number of industrial processes, for example, in the synthesis of ammonia, the Claus process, and the regeneration of the catalyst for the fluid-catalytic-cracking (FCC) process. Another application of O2-enriched air is the most efficient use of methane in high-temperature furnaces or cement kilns. There are different methods for producing O2enriched air, mainly by mixing air with pure O2 obtained from a cryogenic technique or pressure swing adsorption (PSA). However, these techniques require high capital investment and operational costs. Depending on the O2 concentration and the amount of the O2-enriched air needed, membrane technology can be competitive. As organic polymeric hollow-fiber membranes have a separation factor between 2 and 6, a single-stage membrane permeation gives an O2 concentration typically of the order of 30– 50 vol% under a pressure difference of about 10 bar. Although higher O2 concentration and permeability can be achieved by increasing the feed flow rate, by reducing the membrane thickness, or by increasing the pressure difference, these actions increase the separation costs. Furthermore, the organic polymeric membrane cannot be used for the recovery of heat from exhaust gas in high-temperature processes. Herein we propose a new technique to produce O2enriched air by using a mixed-ion and electron-conducting (MIEC) perovskite membrane. The basic idea is shown in Figure 1. At elevated temperatures, under a slight difference in air pressure (1–2 bar) O2 can be transported through a MIEC perovskite membrane in the form of oxygen ions from the side of high air pressure to the side of low air pressure. Simultaneously, electrons are transported in the opposite direction to maintain electric neutrality. The permeated O2 increases the O2 concentration to typically 30–50 vol% in the sweep air that forms the O2-enriched air on the low-pressure side. Therefore, the perovskite membrane combines the in situ O2 supply with permeated O2 and air in one unit thus simplifying the process of O2 enrichment and reducing the operational and capital costs. The obvious advantage of using perovskite membranes is their 100% selectivity for O2. Usually, polymeric membranes also transport noble or inert gases such as Ar or CO2, which can be disadvantageous depending on the process. Synthesis gas for ammonia production, for example, is prepared at a pressure level of about 30 bar and afterwards compressed to a pressure of typically 170–190 bar. Any inert gases contained within the synthesis gas are also compressed to a higher pressure and fed into the synthesis loop. This in turn increases the energy expenditure for compression, the necessary loop volume, and the purge flow used to get rid of the inert components in the synthesis loop. Moreover, compared with hollow-fiber membranes made from organic polymers, the perovskite hollow-fiber membrane requires a lower pressure difference (1–2 bar) across the membrane and can work at elevated temperatures, thus allowing high-temperature heat exchange. O2-enriched air is used mostly in high-temperature oxidation processes such as in the generation of synthesis gas for ammonia production in which O2-enriched air is used to run a secondary reformer typically operated at 1000 to 1100 8C. Therefore, in this process the temperature required to operate the perovskite hollow fiber is already available and can be used by heat exchange. Furthermore, the heat used for the O2 enrichment is not consumed, for example, in an endothermic reaction and can be regained by heat exchange with the product streams that leave the O2-permeation-membrane module. A similar setup may also apply to other applications for O2 enrichment with perovskite membranes, for example, the temperature increase of firing systems in power plants or industrial furnaces. The perovskite of composition BaCoxFeyZrzO3 d (BCFZ; x+y+z= 1.0) is a novel O2-permeable membrane with high O2 permeation fluxes and excellent thermal and mechanical stability. 5] BCFZ was used in a hollow-fiber configuration as [*] Dr. H. Wang, Prof. Dr. J. Caro Institut f!r Physikalische Chemie und Elektrochemie Universit,t Hannover Callinstrasse 3–3A, 30167 Hannover (Germany) Fax: (+49)511-762-19121 E-mail: haihui.wang@pci.uni-hannover.de

Ordering-Induced Microstructures and Microwave Dielectric Properties of the Ba(Mg1/3Nb2/3)O3–BaZrO3 System

Abstract: The structures of compositions across the Ba(Mg 1/3 Nb 2/3 )-O 3 -BaZrO 3 (BMN-BZ) system have been examined using X-ray diffractometry and transmission electron microscopy, and their dielectric properties have been characterized in the microwave range Although pure BMN adopts a 1:2 ordered structure, of space group Pm31, additions of 5-15 mol% BZ stabilize a cubic (Fm3m), 1:1 ordered phase with a doubled perovskite repeat At higher levels of substitution (>25 mol% BZ), the B-site cations are disordered After normal sintering, the niobates in the 1:1 phase field are comprised of nanometer-sized ordered domains that are dispersed in a disordered matrix However, by reducing the cooling rate to 10°C/h, a fully ordered microstructure is formed with domain sizes >100 nm in size The structure of the 1:1 phases has been interpreted using a random-layer model, in which one site is occupied by niobium, and the second is occupied by a random distribution of the remaining cations The addition of small concentrations of BZ produces a 100% improvement in the dielectric-loss properties of BMN, and a Qf value of 82000 is obtained for a 5 mol% substitution

Artificial charge-modulation in atomic scale perovskite titanate superlattices

Abstract: The nature and length scales of charge screening in complex oxides are fundamental to a wide range of systems, spanning ceramic voltage-dependent resistors (varistors), oxide tunnel junctions and charge ordering in mixed-valence compounds. There are wide variations in the degree of charge disproportionation, length scale, and orientation in the mixed-valence compounds: these have been the subject of intense theoretical study, but little is known about the microscopic electronic structure. Here we have fabricated an idealized structure to examine these issues by growing atomically abrupt layers of LaTi3+O3 embedded in SrTi4+O3. Using an atomic-scale electron beam, we have observed the spatial distribution of the extra electron on the titanium sites. This distribution results in metallic conductivity, even though the superlattice structure is based on two insulators. Despite the chemical abruptness of the interfaces, we find that a minimum thickness of five LaTiO3 layers is required for the centre titanium site to recover bulk-like electronic properties. This represents a framework within which the short-length-scale electronic response can be probed and incorporated in thin-film oxide heterostructures.

Intergranular giant magnetoresistance in a spontaneously phase separated perovskite oxide.

Abstract: We present small-angle neutron scattering data proving that, on the insulating side of the metal-insulator transition, the doped perovskite cobaltite ${\mathrm{L}\mathrm{a}}_{1\ensuremath{-}x}{\mathrm{S}\mathrm{r}}_{x}{\mathrm{C}\mathrm{o}\mathrm{O}}_{3}$ phase separates into ferromagnetic metallic clusters embedded in a nonferromagnetic matrix. This induces a hysteretic magnetoresistance, with temperature and field dependence characteristic of intergranular giant magnetoresistance (GMR). We argue that this system is a natural analog to the artificial structures fabricated by depositing nanoscale ferromagnetic particles in a metallic or insulating matrix; i.e., this material displays a GMR effect without the deliberate introduction of chemical interfaces.

Structure and property investigation of a Bi-based perovskite solid solution: (1−x)Bi(Ni1∕2Ti1∕2)O3–xPbTiO3

Abstract: Extending the investigations on Bi-based perovskite solid solutions for high-temperature piezoelectric ceramics, this paper considers the binary solid-solution system (1−x)Bi(Ni1∕2Ti1∕2)O3–xPbTiO3 [(1−x)BNT–xPT] for 0.39⩽x⩽1.00. High-density polycrystalline ceramics were fabricated using conventional solid-state processing methods. These ceramics are then taken for structural and electrical properties and differential scanning calorimetry measurements. A morphotropic phase boundary (MPB) was found at the composition 0.51BNT–0.49PT, with a corresponding paraelectric-ferroelectric phase transition TC≈400°C. The electrical poled ceramics demonstrated piezoelectric d33 coefficients≈260pC∕N at room temperature for the MPB BNT–PT compositions. Experimental data are also given for the influence of MnO2 doping to the BNT–PT system close to the MPB compositions, noting an improvement in dielectric losses but a reduction in d33≈180pC∕N. Tricritical behavior is also identified in the tetragonal phase field, with a T...

Sol‐Gel Route to Ferroelectric Layer‐Structured Perovskite SrBi2Ta2O9 and SrBi2Nb2O9 Thin Films

Abstract: Precursors for layer-structured perovskite thin films of SrBi 2 Ta 2 O 9 (SBT) and SrBi 2 Nb 2 O 9 (SBN) were prepared by the reactions of a strontium-bismuth double methoxyethoxide and tantalum or niobium methoxyethoxide in methoxyethanol, followed by partial hydrolysis. Several spectroscopic techniques, such as 1 H-, 13 C-, and 93 Nb-NMR (nuclear magnetic resonance), and Fourier-transform infrared spectroscopy were used to analyze the arrangement of the metals and oxygen in the precursor molecules. The precursors contained Sr-O-M (where M is Ta or Nb) bonds (i.e., a strontium is connected to two MO 6 octahedra) and Sr-O-Bi bonds with a bismuth atom bonded to the oxygens of the MO 6 octahedron. The arrangement of metals and oxygens was considered to be similar to the layer-structured perovskite crystal sublattice. As a result, the sol-gel-derived SBT thin films crystallized, by rapid thermal annealing in an oxygen atmosphere below 550°C, and they exhibited preferred (115) orientation. The crystallinity improved and the crystallite size increased with temperature up to 700°C. In the case of SBN thin films, a low heating rate (2°C/min) was necessary for the control of the crystallographic (115) orientation, whereas a rate of 200°C/s (rapid thermal annealing) produced films that exhibited c-axis orientation. The (115) SBT thin film, heated to 700°C, exhibited improved ferroelectric properties.