SBT Ceramics Research Articles

Dielectric, energy storage, and charge–discharge properties of Yb‐modified Sr0.7Bi0.2TiO3 relaxor ferroelectric ceramic

AbstractDielectric capacitors have been widely studied in advanced electronics systems due to their rapid discharge rate and high‐power density. Among them, relaxor ferroelectrics characterized by nanodomains possess broad application prospects as dielectric materials with high energy density and high efficiency. In this paper, the dielectric characteristics, energy storage performance, and charge–discharge behavior of rare‐earth Yb‐doped Sr0.7Bi0.2TiO3 ceramics are systematically investigated. The Yb‐doped SBT ceramics reduced the grain size, improved the insulation and thermal conductivity, and significantly improved the dielectric breakdown strength. Finally, a high recoverable energy density of 2.32 J/cm3 and an excellent energy storage efficiency of 92.2% were obtained at 300 kV/cm. In addition, pulsed charge–discharge tests show that Sr0.7Bi0.15Yb0.05TiO3 possesses a rapid discharge rate and high‐power density with superior thermal stability. Based on these outstanding characteristics, Sr0.7Bi0.15Yb0.05TiO3 exhibits promising applications in pulsed power systems.

Simultaneously achieving high energy storage and charge-discharge performance by Nd-doped Sr0.7Bi0.2TiO3 lead-free relaxor ferroelectric ceramics

Dielectric capacitors have been extensively studied in electronic and power systems based on their high power density and ultra-fast discharge rates. In this study, the dielectric, energy storage and charge-discharge properties of Sr0.7Bi0.2TiO3-based lead-free relaxor ferroelectric ceramic were investigated. The dielectric breakdown strength was significantly improved by introducing the rare earth element Nd, which was attributed to the rise in resistivity and large band gap. The results show that Sr0.7Bi0.15Nd0.05TiO3 obtain a high recoverable energy storage density of 2.34 J/cm3 with high efficiency of 92%. In addition, pulsed charge-discharge tests demonstrated that Sr0.7Bi0.15Nd0.05TiO3 possesses a high power density of 73.5 MW/cm3, a short discharge period of 0.1 μs, and a pulsed discharge energy density of 2.0 J/cm3. Meanwhile, the energy storage performance of Sr0.7Bi0.15Nd0.05TiO3 exhibits excellent stability of temperature, frequency and cycling. This work provides a systematic study and a new strategy for enhancing the performance of SBT ceramics.

Investigation of Dielectric, Ferroelectric and Conduction Behavior of Dy3+ Substituted SrBi2Ta2O9 Bismuth Layer Structured Ceramics

The present manuscript explores the impact of Dy doping in the Tantalum based bismuth layer structured ferroelectrics with chemical composition of Sr(Bi1-xDyx)2Ta2O9 (where x = 0.00, 0.025, 0.05, 0.075 and 0.10) prepared by mixed oxide process. X-ray diffraction study of all the ceramics implement orthorhombic phase without any secondary phase. The polycrystalline nature and grain distribution in the materials is studied from scanning electron microscope study. The temperature dependent dielectric performance of Dy doped SBT ceramics at selected frequencies indicates diffuse order phase transitions with reduction in transition temperature (Tc) and relative permittivity with doping level. The residual polarization and coercive field reduce with doping. The conduction mechanism was analyzed using the frequency and temperature domain impedance spectroscopy for all composition. The electrical contribution from both grains and grain boundary in the doped ceramics in the reported temperatures is confirmed from the Nyquist plots and the non-Debye type of relaxation mechanism is manifested from the depressed semicircles in all of them. The ac conductivities variation with frequencies at the studied temperatures follow Jonscher’s power law and the fitting parameters suggests that the conduction mechanism obey the correlated barrier-hopping model.

Boosting of Magnetic, Ferroelectric, Energy Storage Efficiency, and Piezoelectric Properties of Zn Intercalated SrBi4Ti4O15-Based Ceramics.

An appropriate amount of Zn-ions are incorporated into the high Curie temperature bismuth layer-structure ferroelectric material to fabricate Sr0.2Na0.4Pr0.4Bi4Ti4O15:xwt%ZnO; (SNPBT:xZn), with x = 0, 0.10, 0.15, and 0.20 ceramic series to investigate the magnetic, ferroelectric, and energy storage efficiency and piezoelectric properties. Pure SNPBT and SNPBT:xZn ceramics have maintained their structure even after the intercalation of Zn-ions at the lattice sites of SNPBT. The addition of ZnO in SNPBT has improved the multifunctional properties of the material at x = 0.15. At room temperature, SNPBT:0.15Zn has shown a high relative density of 96%, exhibited weak ferromagnetic behavior along with a low saturation magnetization (Ms) of 0.028 emu/g with a low coercive field of 306 Oe, a high remnant polarization (Pr) of 9.04 µC/cm2, a recoverable energy density () of ~0.5 J/cm3, an energy conversion efficiency (η) of ~41%, a high piezoelectric co-efficient (d33) of 21 pC/N, and an impedance of 1.98 × 107 Ω, which are much improved as compared to pure SBT or pure SNPBT ceramics. Dielectric Constant (ɛr) versus temperature plots present the sharp peak for SNPBT:0.15Zn ceramic at a Curie temperature (TC) ~ 605 °C, confirming the strong ferroelectric nature of the ceramic. Moreover, SNPBT:0.15Zn ceramic has shown strong, piezoelectric, thermally stable behavior, which remains at 76% (16 pC/N) of its initial value even after annealing at 500 °C. The achieved results clearly indicate that SNPBT:0.15Zn ceramic is a promising candidate for future wide-temperature pulse power applications and high-temperature piezoelectric devices.

The effect of rare-earth oxides on the energy storage performances in BaTiO3 based ceramics

In this work, 0.7BaTiO3-0.3Sr0.2Bi0.7TiO3 (0.7BT-0.3SBT) ceramics with 0.15 mol% various rare-earth oxides doped are designed and synthesized by the conventional solid-state route. All prepared samples exhibited a single perovskite phase and dense microstructure with fine grain size (0.2–0.5 μm) after sintering at 1180 °C. Especially, the Gd-doped 0.7BT-0.3SBT ceramics exhibited excellent energy storage performances; the corresponding recoverable energy density and efficiency were 3.2 J/cm3 and 91.5% under an electric field of 330 kV/cm, respectively. Meanwhile, doping with Gd caused the BT-based ceramics to possess excellent temperature (30–150 °C) and outstanding frequency stabilities (10–1000 Hz). Moreover, the pulsed charge-discharge experiments revealed that a high power density of 59 MW/cm3 and a fast discharge speed of 110 ns with outstanding temperature stability could be synchronously obtained in the Gd-doped composition. All these features are attractive for pulsed power applications.

Bi0·5Na0·5TiO3–Sr0.85Bi0·1TiO3 ceramics with high energy storage properties and extremely fast discharge speed via regulating relaxation temperature

Bi0·5Na0·5TiO3-based relaxor ferroelectric ceramics have recently gained increasing attention due to their outstanding energy storage properties. However, the trade-off between the recoverable energy storage density/efficiency and discharge rate resulted from the hysteresis of domain switching process, severely limits their applications. Herein, a strategy realizing synergistic excellent energy storage properties and fast discharge rate is proposed through regulating relaxation temperature. The relaxation temperature was decreased to below room temperature by introducing Sr0·85Bi0·1TiO3 into Bi0·5Na0·5TiO3 [(1-x)Bi0·5Na0·5TiO3-xSr0.85Bi0·1TiO3, x = 0.5–0.7)], enabling the small size and weak correlation polar nanoregions (PNRs) with relatively high polarization. The trade-off was overcome by reducing the hysteresis of electrical switching of weak correlation PNRs. Thus, large recoverable energy storage density of 2.32 J/cm3 and high efficiency of 80.1% (250 kV/cm) were achieved simultaneously for x = 0.7 ceramics. Meanwhile, extremely rapid discharge rate (<30 ns) and remarkable power density of 63.7 MW/cm3, which were superior to the previously reported lead-free ceramics were realized. Besides, the 0.3BNT-0.7SBT ceramics also possess good thermal stability over 25 °C–115 °C at 100 kV/cm and good frequency stability (5–100 Hz). These properties make the 0.3BNT-0.7SBT ceramic an ideal candidate for energy storage applications.

Effect of V2O5 B-site substitution on the microstructure, Raman spectrum, and dielectric properties of SrBi2Ta2O9 ceramics

Strontium bismuth tantalate vanadate [SrBi2(Ta2−xVx)O9, SBTV] ceramics, which are bismuth-layered perovskite ferroelectrics, were synthesized through the solid-state reaction method. The effects of different sintering temperatures and V2O5 contents on the structure of the microstructure, Raman spectrum, and dielectric properties of the SBTV ceramics were investigated. As sintered at high temperature (980–1040 °C) and different V2O5 contents (x = 0.1 − x = 0.4), only disk-like grains of the SBTV ceramics were observed in the scanning electron micrographs. Preferential orientation of the crystals of the SBTV ceramics was confirmed through X-ray diffraction studies. The higher dielectric constant and Curie temperature of the SBTV ceramics compared with those of strontium bismuth tantalite (SrBi2Ta2O9, SBT) ceramics are ascribe to the partial replace of Ta5+ ions by V5+ ions in the B sites. The Curie–Weiss law and the modified Curie–Weiss law were used to discuss the normal-type or relaxor-type ferroelectric characteristic of the SBTV ceramics. The Ta5+ ion replaced by V5+ ion site in SBT ceramics to form SBTV ceramics exerted a pronounced effect on the BO6 mode, as demonstrated by Raman spectrum results.

Microstructural, dielectric and ferroelectric properties of Sr0.8Bi2.15Ta2O9 ceramics synthesized by microwave processing technique

ABSTRACTSr0.8Bi2.15Ta2O9 (SBT) ceramics were synthesized by microwave-assisted solid-state reaction route. SBT ceramics were sintered at three different temperatures namely 1050°C, 1100°C and 1150°C for 30 min, respectively. XRD study confirmed the retention of single phase of SBT ceramics sintered at 1050°C and 1100°C. Plates like with non-uniform distribution of grains were observed from the FESEM study. Dielectric constant and dielectric loss were found to decrease with the increase of sintering temperature. From room temperature P–E loop study, remnant polarization and coercive field were found to increase with the increase in sintering temperature. From the J–E plot study, leakage current was found to decrease with the increase in sintering temperature. Minimal degradation of polarization was obtained from fatigue characteristics. SBT ceramics sintered at 1100°C show better ferroelectric properties and make it suitable for memory applications.

Influence of Na, Sm substitution on dielectric properties of SBT ceramics

Abstract Sodium, Samarium substituted Strontium Bismuth Titanate (Sr1-xNaxSmxBi4Ti4O15 –SNSBT where x = 0.1, 0.2, 0.3, 0.4) piezoelectric ceramics are synthesized by solid-state sintering route using high energy planetary ball mill for 20 h in presence of Acetone and Aqua media. Calcination and sintering are carried out at 800 °C and 1160 °C respectively in Air using programmable furnace. 1 mm thickness and 10 mm diameter circular pellets are prepared by uniaxial hydraulic press at 4 tons/cm2 pressure. Larger surfaces of the sample are coated with silver in order to have good electric contact for properties study. X-Ray Diffraction and Scanning Electron Microscopy studies are carried out to identify the orthorhombic structure, grain size and grain orientation. SEM shows densified and plate like structure of SNSBT. Experimental density is found to be more than 95% of theoretical density. Tolerance factor is decreased with increase of Na, Sm concentrations of SNSBT ceramics. Dielectric measurements are conducted as function of temperature at various frequencies and phase transition temperature (Tc) is enhanced by addition of Na, Sm of SBT.

Synthesis and investigation of RE(III) cation substituted SBN and SBT ceramics

ABSTRACTPhysico-chemical, structural and electric properties of Aurivillius phases SrBi2-xSmxNb2O9 and SrBi2-ySmyTa2O9 with x = 0.0 and 0.4 obtained in muffle and microwave furnace have been investigated by the X-ray diffraction, DTA, FTIR-spectroscopy and dielectric spectroscopy methods. The perovskite-like structure of solid solutions obtained is characterized by the orthorhombic symmetry. The assumption about the non-statistical distribution of Sm(III) cations crystal structure of Aurivillius phases was made according to the obtained results. It has been found that Sm(III) cations introduction does not influence on TC of SrBi2-xSmxNb2O9 solid solutions.

Thermal stabilities of electromechanical properties in cobalt-modified strontium bismuth titanate (SrBi4Ti4O15)

Bismuth layer-structured ferroelectric (BLSF) strontium bismuth titanate (SrBi4Ti4O15, SBT) ceramic oxides with B-site cobalt substitutions have been synthesized using conventional solid–state reaction. The dielectric, piezoelectric, and ferroelectric properties of cobalt-modified SBT are investigated in detail. The results indicate that cobalt is very effective in promoting the piezoelectric performance of SBT. The SBT modified with 3 mol% Co3+ (SBT-3Co) exhibits the optimized piezoelectric properties, with a piezoelectric constant d33 of 28 pC/N, which is the highest value among the modified SBT-based piezoelectric ceramics ever reported. The temperature-dependent electrical impedance, resonance frequencies, and electromechanical coupling factors (kp and kt) reveal that the cobalt-modified SBT ceramics have good thermal stabilities of electromechanical properties up to 300 °C. These results demonstrate that the cobalt-modified SBT ceramics are promising materials for high temperature piezoelectric sensors applications.

Structure and electric properties of cerium substituted SrBi1.8Ce0.2Nb2O9 and SrBi1.8Ce0.2Ta2O9 ceramics

SrBi1.8Ce0.2Nb2O9 (SBCN) and SrBi1.8Ce0.2Ta2O9 (SBCT) powders were prepared via solid-state reaction method. X-ray diffraction analysis reveals that the SBCN and SBCT powders have the single phase orthorhom-bic Aurivillius structure at room temperature. The contribution of Raman scattering and FTIR spectroscopy of these samples were relatively smooth and resemble each other. The calcined powders were uniaxially pressed and sintered at 1250?C for 8 h to obtaine dense ceramics. Dielectric constant, loss tangent and AC conductivity of the sintered Ce-doped SrBi2Nb2O9 and SrBi2Ta2O9 ceramics were measured by LCR meter. The Ce-doped SBN (SBCN) ceramics have a higher Curie temperature (TC) and dielectric constant at TC (380?C and ?? ~3510) compared to the Ce-doped SBT (SBCT) ceramics (330?C and ?? ~115) when measured at 100Hz. However, the Ce-doped SBT (SBCT) ceramics have lower conductivity and dielectric loss.

Dielectric, Polarization and Strain Response of Enhanced Complex Ceramics: The Study through Pb(Zr0.52Ti0.48)O3-SrBi2Ta2O9

Electrical properties of the (1-x)PZT-xSBT ceramics (0.1≤x≤0.3) were investigated in comparison with pure PZT and SBT ceramics. It was found that the dielectric constant increased with small addition of SBT (x = 0.1) into PZT. The hysteresis loop measurement demonstrated that the PZT-SBT ceramics showed larger remanent polarization than pure PZT and less coercive filed than pure SBT ceramic. Strain behavior showed a symmetric butterfly curve in the compositions with 0≤x≤0.3 but the low strain obtained was found in pure SBT. This research suggested that 0.9PZT-0.1SBT ceramic is a promising material to be further utilized in ferroelectric memory devices.

Piezoelectric properties and thermal stabilities of strontium bismuth titanate (SrBi4Ti4O15)

Bismuth layer-structured ferroelectric (BLSF) compound strontium bismuth titanate (SrBi4Ti4O15, SBT) with cerium modifications have been synthesized using conventional solid-state processing. X-ray powder diffraction (XRPD) analyses reveal that the cerium-modified SBT ceramics have a pure four-layer Aurivillius-type structure. The dielectric, ferroelectric, and piezoelectric properties of the cerium-modified SBT ceramics are investigated in detail. The results indicate that the cerium modifications into SBT increase the densities, decrease the sintering temperature, lower the dielectric loss tanδ, and reduce the coercive filed Ec. The piezoelectric measurements show that cerium is very effective in promoting the piezoelectric properties of SBT ceramics. The SBT ceramics modified with 4mol% CeO2 (SBT-4Ce) exhibit the optimized piezoelectric properties, with a piezoelectric constant d33 of 27pC/N, which is the highest value among the modified SBT-based piezoelectric ceramics ever reported. The temperature-dependent electrical impedance and electromechanical coupling coefficients (kp and kt) reveal that the electromechanical coupling characteristics have a significant deterioration at ~400°C because of the high conductivity at high temperature. But the temperature-dependent frequency constants (Np and Nt) and thermal annealing analyses indicate the cerium-modified SBT ceramics have good thermal stabilities of piezoelectric properties up to 450°C. These results demonstrate that the cerium-modified SBT ceramics are promising materials for high temperature piezoelectric sensors applications.

Improved ferroelectric and pyroelectric properties of Pb-doped SrBi4Ti4O15 ceramics for high temperature applications

• Sr 1−x Pb x Bi 4 Ti 4 O 15 (SPBT, x = 0 − 0.4) ceramics were synthesized by soft chemical method. • X-ray diffraction analysis confirmed the formation of bismuth layered structure. • SEM images showed plate like grain morphology with random orientation of plate faces. • Pb-doping resulted in improved ferroelectricity of SrBi 4 Ti 4 O 15 ceramics. • Pb-doped SrBi 4 Ti 4 O 15 exhibited improved pyroelectric properties with high T C . Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr 1− x Pb x Bi 4 Ti 4 O 15 ( x = 0–0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient ( d 33 ) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40 mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer–Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications.

Influence of sintering temperature on energy storage properties of BaTiO3–(Sr1−1.5xBix) TiO3 ceramics

The effect of sintering temperature on microstructure, dielectric properties and energy storage properties of BaTiO3–(Sr1−1.5xBix)TiO3 (x=0.09) (BT–SBT) ceramics was investigated. The sintering temperature has pronounced influence on the grain size, shrinkage, and dielectric properties of the BT–SBT ceramics. With increasing sintering temperature, the dielectric constant increases largely. However, the increasing tendency of the dielectric breakdown strength (BDS) is less noticeable but become more evident with the consideration of Weibull modulus. For the BT-SBT ceramics, the unreleased energy density decreases and the electric field stability of the energy storage efficiency enhances with the increase of sintering temperature.

Ferroelectric and Piezoelectric Studies on Mo—Substituted SrBi2Ta2O9 Ferroelectric Ceramics

Samples of compositions SrBi2MoxTa2-xO9 (SBMT), with x = 0.0, 0.025, 0.050, 0.075, 0.10 have been synthesized by solid-state reaction method taking SrCO3, Bi2O3, Ta2O5 and MoO3 in their stoichiometric ratios. X-ray diffraction patterns of the samples confirm the formation of single phase layered perovskite structure in the samples with x up to 0.05. The effect of Mo+6 substitution on the dielectric behavior of SBT was studied by measuring the capacitance and tangential loss using an impedance analyzer (HP 4294A). The temperature dependence of dc conductivity vis-á-vis molybdenum content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The ferroelectric and piezoelectric studies of the Mo substituted SBT ceramics show that the remanent polarization and d33 values increase with increasing concentration of molybdenum.

Effect of sintering temperature on the structural, dielectric and ferroelectric properties of tungsten substituted SBT ceramics

Structural, dielectric and ferroelectric properties of tungsten (W) substituted SrBi 2(Ta 1− x W x ) 2O 9 (SBTW) [ x=0.0, 0.025, 0.05, 0.075, 0.1 and 0.2] have been studied as a function of sintering temperature (1100–1250 °C). X-ray diffraction patterns confirm the single-phase layered perovskite structure formation up to x=0.05 at all sintering temperatures. The present study reveals an optimum sintering temperature of 1200 °C for the best properties of SBTW samples. Maximum T c of ∼390 °C is observed for x=0.20 sample sintered at 1200 °C. Peak-dielectric constant ( ε r ) increases from ∼270 to ∼700 on increasing x from 0.0 to 0.20 at 1200 °C sintering temperature. DC conductivity of the SBTW samples is nearly two to three orders lower than that of the pristine sample. Remnant polarization ( P r) increases with the W content up to x≤0.075. A maximum 2 P r (∼25 μC/cm 2) is obtained with x=0.075 sample sintered at 1200 °C. The observed behavior is explained in terms of improved microstructural features, contribution from the oxygen and cationic vacancies in SBTW. Such tungsten substituted samples sintered at 1200 °C exhibiting enhanced dielectric and ferroelectric properties should be useful for memory applications.

Effect of W Substitution in Strontium Bismuth Tantalate Ferroelectric Ceramics: Enhanced Ferroelectric Properties

AbstractTungsten (W)-substituted SBT ceramics [SrBi2(Ta1-xWx)2O9; 0.0 ≤ x ≤ 0.20] were synthesized by solid state reaction method using different sintering temperatures (1100 οC, 1150 οC, 1200 οC and 1250 οC). W substitution is found to significantly affect the electrical properties of SBT, including dielectric permittivity, Curie temperature, and ferroelectricity. Dielectric constant (εr) and the Curie temperature (Tc) increase with increasing W content. The dielectric loss reduces significantly with increase in W concentration. The maximum Tc of ~ 390 οC is observed in the sample with x = 0.20 as compared to ~ 320 οC for the pure sample when sintered at 1200 οC. The peak ε increases from ~ 270 in the sample with x = 0.0 to ~ 700 for the composition with x = 0.20, when sintered at 1200 οC. All the tungsten-substituted ceramics have higher 2Pr than that in the pristine sample. The maximum 2Pr (~25 μC/cm2) is obtained in composition with x = 0.05 sintered at 1200 οC. These effects have been interpreted based on the model of the recovery of oxygen vacancies upon W substitution. Such compositions with low loss and high Pr values should be excellent materials for highly stable ferroelectric memory devices.

Ferroelectric and piezoelectric properties of tungsten substituted SrBi 2Ta 2O 9 ferroelectric ceramics

Tungsten substituted samples of compositions SrBi 2(W x Ta 1− x ) 2O 9 ( x = 0.0, 0.025, 0.050, 0.075, 0.10 and 0.20) were synthesized by solid-state reaction method and studied for their microstructural, electrical conductivity, ferroelectric and piezoelectric properties. The X-ray diffractograms confirm the formation of single phase layered perovskite structure in the samples with x up to 0.05. The temperature dependence of dc conductivity vis-à-vis tungsten content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The ferroelectric and piezoelectric studies of the W-substituted SBT ceramics show that the remanent polarization and d 33 values increases with increasing concentration of tungsten up to x ≤ 0.05. Such compositions with low conductivity and high P r values should be excellent materials for highly stable ferroelectric memory devices.