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The Al 2 O 3 -modified Pb 0.99 (Zr 0.95 Ti 0.05 ) 0.98 Nb 0.02 O 3 (PZT 95/5) ferroelectric ceramics with enhanced breakdown strength were prepared from PZT 95/5 powders coated with a thin Al 2 O 3 shell layer, which were fabricated by a Citrate-Chelation method followed by a conventional sintering process. The microstructure and electrical properties of the as-prepared ceramics as a function of Al 2 O 3 content were systematically investigated. The results reveal that Al 2 O 3 nanoparticles are successfully coated on PZT 95/5 powders to form the core–shell structure and well dispersed at the grain boundaries of the PZT 95/5 ceramic matrix after sintering, which strengthened the grain boundaries. In particular, compared with pure PZT 95/5 ferroelectric ceramics, PZT 95/5 ceramics with less than 1.0 wt% Al 2 O 3 inclusion possess the enhanced breakdown strength and energy density, of which the largest increment being 25.9% and 13.5%, respectively. It is indicated that the as-prepared PZT 95/5 ferroelectric ceramics may be a promising candidate for explosively driven power supply. [ABSTRACT FROM AUTHOR]

We present a study on the hydrothermal synthesis of BaTiO 3 utilizing NaTi 3 O 6 (OH)- (H 2 O) 2 nanowires, which was conducted by controlling temperature, alkalinity and time. Initially, increased temperature has promoted the synthesis of BaTiO 3 and induce a change in the morphology. When the temperature increases within the range of 90 °C–210 °C, the morphology of the product transitions from nanoparticle to spindle-shaped to nanowires. Then, a time-dependent experiment was conducted to investigate the mechanisms involved in the transformation of the morphology. The formation of nanoparticle occurs through the process of dissolution-crystallization, while the formation of BaTiO 3 nanowires is attributed to hydrothermal ion exchange. Also, the hydrothermal process is characterized by grain aggregation and grain growth. By investigating the synthesis and morphology evolution of BaTiO 3 , this work holds significant potential for the synthesis of BaTiO 3 nanowires or other perovskite-type MTiO 3 employing titanate as a precursor. [ABSTRACT FROM AUTHOR]

The ultrahigh piezoelectric coefficient (d 33 ≥ 1000 pC/N) exhibited by piezoelectric Pb(Zr,Ti)O 3 (PZT) ceramics not only captivates researchers but also holds considerable practical value across various applications. While significant progress has been made in enhancing piezoelectricity of PZT-based ceramics, novel mechanisms need to be proposed to explain the piezoelectric behavior of new systems with ultrahigh d 33. In this study, we initially employ LiNbO 3 as an additive to enhance the piezoelectric properties of the Pb(Ni 1 / 3 Nb 2 / 3)O 3 –PbZrO 3 –PbTiO 3 ceramics. and the optimal performance is achieved by incorporating 1.5 mol% of LiNbO 3 into the system, resulting in an ultrahigh d 33 ∼1178 pC/N (d 33 * ∼1560 p.m./V (@ E = 5 kV/cm)). The corresponding mechanism for this superior piezoelectric response involves the AB-site co-doping effect, especially the (Li Pb ′ − Nb Zr / Ti ∙) defect dipoles formed by the introduction of LiNbO 3. In particular, the addition of LiNbO 3 leads to a more uniform distribution of domain sizes, thereby further enhancing the ultrahigh piezoelectricity. These findings pave the way for a deeper under-standing of the origin of ultrahigh piezoelectric properties and make substantial contributions to the advancement of piezoelectric materials for practical applications in electromechanical devices. [ABSTRACT FROM AUTHOR]

Due to the high demand for dielectric materials with high energy density, the energy storage performance of antiferroelectric ceramic capacitors has always gained much attention. Polarization intensity is a key factor that is closely related to the energy storage density. However, thus far, there has been a lack of research studies or successful methods to effectively modulate polarization intensity. The behavior of the polarization process is complex and contains domain nucleation, growth, and flip-flapping. Based on this finding, the introduction of Nb5+ at the B-site was designed to influence the three stages of antiferroelectric polarization by regulating the balance between the ferroelectric and antiferroelectric phases, and eventually realized regulation of the saturation polarization intensity in the (Pb 1-1.5x La x)(Zr 0.5 Sn 0.43 Ti 0.07)O 3 antiferroelectric ceramics. The saturation polarization intensity has increased from 25.56 to 42 μC/cm2 with Nb5+ content increases from 0 to 4 mol% and the hysteresis was kept low, Pb 0.94 La 0.04 (Zr 0.65 Sn 0.35) 0.975 Nb 0.02 O 3 is the optimal component with a high releasable energy density of 8.26 J/cm3 and an energy storage efficiency of 90.31%. This work provides an in-depth explanation of the microscopic mechanism of antiferroelectric ceramic polarization and presents a novel approach for the composition design of high-energy storage density antiferroelectric ceramics. [ABSTRACT FROM AUTHOR]

With the continuous development of electronic devices, miniaturization and high capacitance have become important factors in the fabrication of multilayer ceramic capacitors (MLCCs) with a Ni internal electrode (Ni-MLCCs). The typical thickness of the dielectric layer of commercial MLCCs is less than 1 μm, which implies a higher capacitance compared to MLCCs with a thicker dielectric layer. In this study, 1210-type Ni-MLCCs were prepared via a tape casting method using a BaTiO 3 powder chemically coated with Dy and Ho additives. The high capacitance (390 nF) Ni-MLCC sintered at 1220 °C exhibited a low dielectric loss (tan δ < 2%), high insulation resistance (>9000 MΩ), and temperature stability comparable to that of the EIA X5R standard (capacitance-temperature coefficient (TCC) = ΔC/C 25 °C ≤ ±15%, between -55–85 °C). Relaxation behavior was observed between 1 Hz and 10 kHz, following the modified Curie–Weiss law and the Vogel–Fulcher relationship. The capacitive temperature stability of Ni-MLCC is closely related to the applied direct current (DC) bias field. The EIA X7R stability (TCC ≤ ±15%, between -55–125 °C) of the Ni-MLCCs at 1220 °C was gained under dc-bias field 3 and 5 V/μm. The capacitance varied as alternating current (AC) electric fields were applied. The grain shell was sensitive to both the DC bias and AC fields, but the grain core was more sensitive to the DC bias electrical field than the AC field. Furthermore, the ferroelectric response in MLCC decreases with rising temperature. [ABSTRACT FROM AUTHOR]

It has been reported that grain size has significant influence on the dielectric properties of barium strontium titanate (BST) thin films. In this paper we have proposed a multilayer structure in which BST layers are separated by thin MgO layers which are expected to function as barrier to atomic diffusion so that the grain size of BST could be confined. By simulation we have found that for a device with a coplanar/composite film/substrate configuration, the introduction of MgO can effectively change the dielectric constant of the composite while the tunability is not significantly affected, provided the amount of MgO is smaller than 25%. A prototype device was prepared to demonstrate the feasibility of this idea. By X-ray diffraction measurements it is revealed that BST and MgO coexist in the composite. The dielectric property of the composite film was determined and it was found that the film has a tunability of up to ~7% at 500 MHz and under an electric field of 13.3 kV/mm. [ABSTRACT FROM AUTHOR]

Solid-state reaction process has been used to fabricate (Sr 0.7 Ca 0.3) z (Zr 0.95 Ti 0.05)O 3 (0.98 ≤ z ≤ 1.04) ceramics, the effects of non-stoichiometric ratio on sintering behavior, microstructure, structural properties and microwave dielectric properties were investigated. The ceramics contain the secondary phase ZrO 2 with Fm-3m and P42 space structure as z ≤ 1.01. Electron back scatter diffraction analysis indicates that the secondary phase is concentrated at the grain boundary, which hinders the grain growth. Based on Rietveld refinement and Raman spectra, the secondary phase content and structural characteristics, including cell parameters, polarizability and lattice vibration anharmonicity, are obtained to establish the correlation between structure and microwave dielectric properties. The relative permittivity depends on the polarizability, and the variation of Q × f values is determined by the combined effects of grain size, secondary phase and lattice intrinsic loss, and is mainly driven by lattice vibration anharmonicity. In addition, the τ f values are affected by lattice distortion. Particularly, (Sr 0.7 Ca 0.3) 1.02 (Zr 0.95 Ti 0.05)O 3 (z = 1.02) ceramics have the optimized microwave dielectric properties: ε r = 35.9, Q × f = 26,000 GHz, τ f = −13 ppm/°C. This work provides a reference for optimizing microwave dielectric properties of materials. [ABSTRACT FROM AUTHOR]

With the increasing demand for the miniaturization, high capacitance and high reliability of the Multilayer Ceramic Capacitor (MLCC), the thickness of single dielectric layer is less than 1 μm and the original partical size of the powder has reached the scale less than 300 nm. In this paper, BaTiO 3 powder of various partical sizes (150–500 nm) was modified with Dy and Ho through a chemical coating method. The dense and uniform ceramics in accordance with EIA X7R-type temperature stability were sintered under low oxygen partial pressure and good dielectric properties of dielectric constant >2000 and dielectric loss <1% were obtained. The grain size effect on the dielectric properties under various dc-bias field were systematically investigated. It is found that the fine-grain ceramic exhibits a lower absolute change of the dielectric constant and a higher dc-bias stability. Furthermore, the modified 150 nm BaTiO 3 powders was made into 1210-type MLCCs, and the dielectric behavior of the MLCCs with different dc-fields and ac-fields were study over −55 °C–125 °C. It is found that the ac electric field had a greater influence on the dielectric properties at room temperature and below, and the dielectric constant variation under a dc-bias field was also greatly advanced for the modified fine-grain MLCCs. The results provide a reference for the design of the next generation of BME-MLCCs. [ABSTRACT FROM AUTHOR]

Barium Strontium Titanate (Ba 1-x Sr x TiO 3 , BST) possesses the advantages of high permittivity, low remnant polarization and dielectric loss, suggesting great potential in the application of power capacitors. However, the low maximum polarization severely restricts the achievement of outstanding energy storage properties (ESP). Herein, we design a lead-free bulk ceramic: (1-x)Ba 0. 55 Sr 0 · 45 TiO 3 -xBi 0.5 Na 0. 5 TiO 3 [(1-x)BST-xBNT] (x = 0.1–0.4), prepared by two-step solid-state reaction method. The introduction of BNT contributes to (1) the boost of maximum polarization (from 21 μC/cm2 up to 32.6 μC/cm2) due to Bi3+ lone pair covalent effect (2) strong relaxor behavior (1.71≪ γ 1.84) derived from weakly coupled nanopolar regions, which can be verified by high activation energy E a = 0.341 eV at x = 0.3, improves the ESP and thermal stability of the ceramics. According to the above strategies, high W rec = 1.73 J/cm3 and η = 84.4% are achieved in the 0.7BST-0.3BNT ceramics at 206 kV/cm, which is preferable to the previous results regarding BST-based bulk ceramics. The excellent thermal stability (20–120 °C), frequency stability (1–500 Hz), as well as anti-fatigue characteristic (cycling number: 105) were obtained in the 0.7BST-0.3BNT. Furthermore, 0.7BST-0.3BNT ceramics exhibit high-power density (P D = 44.9 MW/cm3) and rapid discharge rate (t 0.9 = 99.2 ns) from 20 °C to 120 °C. This work provides a feasible way to achieve good energy storage and charge-discharge properties for pulse power energy storage systems. [ABSTRACT FROM AUTHOR]

(Pb, La)(Zr, Sn, Ti)O 3 (PLZST) ceramic is one of the most prospective antiferroelectric (AFE) materials for variety of functional applications including energy storage and converter. Systematic structural investigation of domain structures should be of fundamental importance for understanding the structure-property relationship in AFE ceramics. In this study, the hierarchical domain structures and modulated structures correlated to the compositional variation in (Pb 0.97 La 0.02) (Zr 0.50 Sn x Ti 0.50-x)O 3 (x = 0.375, 0.45 and 0.50) were observed and investigated in details by transmission electron microscopy. The PLZST ceramics show exclusively incommensurate modulated structures (IMS) whose modulation period changed from 9.37 to 6.15 and to 4.04 with increasing of the x value. The hierarchical domain structures include, in decreasing scales, AFE domains, incommensurate domains and nanodomains. The elementary domains in PLZST ceramics are pinstriped nanodomains which were formed based on IMS configuration but by frequent modulation of IMS periodicity and formation of faults. Nanodomains accumulated and then dissociated into incommensurate domains and AFE domains successively. The presently revealed structural characteristics in antiferroelectric PLZST may stimulate future researches on the evolution of IMS-based hierarchical domains under external physical fields, e.g. thermal or electrical, and their correlation to the physical performance. [ABSTRACT FROM AUTHOR]

In this work, TiO 2 nanowire arrays embedded in PbZrO 3 -based antiferroelectric (AFE) films were fabricated on FTO/glass substrates using a facile two-step method. The energy storage performance was modulated by changing the density and morphology of TiO 2 nanowire arrays. A large recoverable energy density (W re) of 50.6 J/cm3 and efficiency (η) of 61% were achieved, which was attributed to the enhancement of maximum polarization and breakdown strength by constructing TiO 2 nanowire arrays in AFE films. More importantly, the composite films exhibited excellent thermal stability with the variation of energy storage density (<5%) and efficiency (<7%) in a wide temperature range (−120 to 130 °C) at the operating electric field of 1300 kV/cm. The results demonstrate that the composite films have huge potential in the future energy storage applications, whether in cold polar regions or high temperature regions. [ABSTRACT FROM AUTHOR]

Recently, the (Pb,La)(Zr,Ti)O 3 antiferroelectric materials with slim-and-slanted double hysteresis loops have been widely drawn in the application of advanced pulsed power capacitors due to its low strain characteristic. In this work, the energy storage properties of (Pb 0.895 La 0.07)(Zr x Ti 1- x)O 3 ceramics with different Zr contents are researched thoroughly because the substitution of Ti4+ by Zr4+ can reduce the tolerance factor t , enhancing the antiferroelectricity. The polarization-electric field hysteresis loops of the PLZT ceramics become slimmer with increasing Zr content. The highest recoverable energy storage density (W re) of 3.38 J/cm3 and ultrahigh energy efficiency (η) of 86.5% are achieved in (Pb 0.895 La 0.07)(Zr 0.9 Ti 0.1)O 3 ceramic. The (Pb 0.895 La 0.07)(Zr 0.9 Ti 0.1)O 3 ceramic also hold fairly thermal stability (relative variation of W re is less than 28% over 30 °C-120 °C), excellent frequency stability (10–1000 Hz) and good fatigue endurance. These results demonstrate that the (Pb 0.895 La 0.07)(Zr 0.9 Ti 0.1)O 3 ceramic can be a desirable material for dielectric energy storage capacitors, especially for pulse power technology. [ABSTRACT FROM AUTHOR]

Abstract Currently, there is an urgent need of extraordinary comprehensive pyroelectric materials for the wide application in detectors and energy harvesters. In this study, the (Pb 1–1.5 x La x)(Zr 0.86 Ti 0.14)O 3 (abbreviated as PLZT, x = 0.02, 0.03, 0.04 and 0.05) ceramics located in ferroelectric-antiferroelectric (FE-AFE) phase boundary were designed and synthesized by using conventional solid-state reaction method. The microstructures, phase structures, dielectric, ferroelectric, thermal depolarization and pyroelectric properties of the PLZT ceramics with different La content were investigated thoroughly. The XRD results show that the PLZT ceramics change from FE phase to AFE phase with increasing La content. The significant improvement of pyroelectric coefficient p and figures of merit (FOMs) are achieved in the PLZT ceramics with the increase in La content because of the increased metastable ferroelectric phase under the application of electric field. The (Pb 0.955 La 0.03)(Zr 0.86 Ti 0.14)O 3 (x = 0.03) ceramic exhibits not only high p of 5.2 × 10 − 8 C / cm 2 K and high depolarization temperature (T d) of 179 ℃ but also excellent FOMs with F i = 2.2 × 10 − 10 m / V , F v = 5.0 × 10 − 2 m 2 / C , and F d = 3.47 × 10 − 5 Pa − 1 / 2 . In addition, the highest p of 6.8 × 10 − 8 C / cm 2 K is achieved in (Pb 0.94 La 0.04)(Zr 0.86 Ti 0.14)O 3 (x = 0.04) ceramic. These results demonstrate that the PLZT ceramics of x = 0.03 and 0.04 are promising candidates for pyroelectric applications. [ABSTRACT FROM AUTHOR]

Crack-free Yttrium iron garnet (Y 3 Fe 5 O 12 , YIG) thin films were successfully deposited on Si/SiO 2 substrates by RF magnetron sputtering, through controlling the annealing temperature and cooling rate during post-annealing process. The annealing condition dependences of crystallinity, microstructures and magnetic properties of YIG films were investigated. With the increase of the annealing temperature, the saturation magnetization of YIG films increases and the coercive field decreases, while the ferromagnetic resonance (FMR) linewidth becomes wider. The films annealed at 750 °C with cooling rate of 1 °C/min are crack-free and present excellent comprehensive performances, the corresponding coercive field is 32 Oe and the FMR linewidth is 57 Oe at 9.4 GHz. These results indicate that high-quality crack-free YIG films with excellent magnetic properties can be achieved on Si/SiO 2 substrates by controlling the annealing process, which makes it more convenient to fabricate low-loss microwave integrated devices. [ABSTRACT FROM AUTHOR]

Sr 0.30 Ba 0.70 Nb 2 O 6 (SBN30) ferroelectric ceramics were fabricated by conventional sintering (CS) and by hot-pressing sintering (HP) and their crystal structure, microstructure, dielectric, ferroelectric and pyroelectric properties were studied and compared. Preferred orientation of the HP ceramics was detected through X-ray diffraction. Dense microstructure virtually free of pores has been achieved in HP samples. Moreover, the HP samples manifested prominent anisotropy in electrical properties. Besides, the relative permittivity ( ε r ), saturated polarization ( P s ), pyroelectric coefficient ( p ) in the direction perpendicular to the pressing axis were much higher than those of the randomly oriented CS samples. The HP samples sintered under 200 MPa show excellent pyroelectric properties in the direction perpendicular to the pressing axis, with pyroelectric coefficient of 2.38×10 −8 C/cm 2 K and pyroelectric figure of merit of F i =1.13 pm/V, F v =1.89 m 2 /C and F d =0.63 μPa −1/2 ，which roughly triple the values obtained in CS samples. These results indicate that hot-pressing is a viable option for accessing single-crystal-like anisotropy as well as enhanced electrical properties in polycrystalline ceramics, thus unveiling the distinctive potential of HP SBN30 ceramics for infrared detector applications. [ABSTRACT FROM AUTHOR]

Reversible domain switching in aged acceptor-doped ferroelectric ceramics is a powerful method to achieve electrostrain due to the exchange of nonequal crystalline axes of domains. Nevertheless, previous work suggested that the strain obtained via reversible domain switching in unpoled ceramics was much lower than theoretical value. In this paper, we demonstrate that the strain in poled and aged acceptor-doped ferroelectric ceramics can be significantly enhanced when the driving electric field is perpendicular to the poling direction, originating from the exchange of nonequel crystalline axes of more domains. Consequently, the electrostrain of poled and aged 0.1 wt% MnO 2 -doped 0.05Pb(Mn 1/3 Sb 2/3 )O 3 −0.50PbZrO 3 −0.45PbTiO 3 could reach 0.225% which was 4.17 times larger than that of unpoled sample under a low electric field of 15 kV cm −1 . Moreover, the corresponding normalized strain d 33 * reached 1500 pm V −1 which significantly exceeded the values reported in ferroelectric ceramics. Our work provide a general effective method to enhance the electrostrain behavior via reversible domain switching in aged acceptor-doped ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

SrRuO 3 (SRO) thin films were grown on SiO 2 /Si substrates with different thickness of LaNiO 3 (LNO) seed layers by RF magnetron sputtering. Effects of LNO thickness on the grain orientation, surface morphology, magnetic behavior and electrical transport properties of SRO films were investigated. The orientation of SRO films transformed from (110) pc to (001) pc and the residual stress was released gradually with increasing the thickness (pc refers to the pseudo-cubic unit cell of SrRuO 3 ). SRO films with higher orientation grown on LNO exhibited more flat surface, higher saturation magnetization, and lower coercive field. The magnetic anisotropy was enhanced on thicker LNO due to the different states of residual stress. In addition, the temperature dependence of resistivity was promoted by the microstructural disorder. (110) pc -oriented SRO monolayer electrode and (001) pc -oriented SRO/LNO300 bilayer electrode own low room temperature sheet resistance of 0.38 Ω/□ and 0.26 Ω/□, respectively. The results indicate that the controllable SRO films can be used as not only good bottom electrodes but also promising templates to control the crystallographic orientations of various other perovskite-based functional materials. [ABSTRACT FROM AUTHOR]

The correlation between films thickness and the physical properties (such as magnetic, magnetotransport properties) has been investigated in 5 nm and 160 nm La 0.7 Sr 0.3 MnO 3 (LSMO). The films were deposited on (100) SrTiO 3 (STO) substrates by chemical solution deposition method. High-resolution X-ray diffraction (HRXRD) and high-resolution transmission electron microscopy have been used to estimate the epitaxial structure and the change of strain. Both of the films are grown on STO substrates with coherent interfaces. The thinner sample has fully strained while the thicker film is partially strain relaxation. With decreasing film thickness from 160 to 5 nm, both of the T C and T MI strongly depressed. The strain and limitation of the spin fluctuations by the film thickness are the main origins of the Tc lowering. The MR value of S1 is much larger than that of S2 at 300 K. It can be elucidated by the existence of magnetic polarons around T C and spin fluctuations in the interface between the film and the substrate. [ABSTRACT FROM AUTHOR]

La 0.7 Ca 0.3 MnO 3 (LCMO)/La 0.7 Sr 0.3 MnO 3 (LSMO) multilayer films have been successfully prepared on (100) oriented SrTiO 3 substrates by chemical solution deposition method. The relationship between the multilayer structure and physical properties was systematically studied. X-ray diffraction (HRXRD) patterns of θ−2θ scan show that both of the films have perfect crystalline orientation. Reciprocal space maps (RSM) of the multilayer films show that the multilayer films are epitaxial growth and fully strained. Independent ferromagnetic - paramagnetic transition of LCMO and LSMO layer are visible as a function of the temperature, which indicates that the magnetization of the individual layers can rotate independently of each other. The maximum value of absolute MR is increased slightly as the layer number increasing. It can be attributed to the spin-polarized tunneling which is associated with magnetic domain rotation at the interface. [ABSTRACT FROM AUTHOR]

La 0.7 Ca 0.3− x Sr x MnO 3 ( x =0, 0.10, 0.15, 0.25 and 0.30) thin films were prepared by the sol–gel method on Si substrates. The structural, magnetic and transport properties were systematically studied. All the LCSMO thin films crystallized perfectly with a random crystalline orientation. The films show strong coupling between lattice and physical properties. With the increment in x , the lattice parameter increases, the magnetic properties are enhanced, and the T c increases monotonically from 235 K to 343 K. Resistivity is dramatically decreased with Sr dopant. The temperature corresponding to the MR maxmium value is close to that of the T MI for LCMO, while there was no peak value for Sr doped thin films in this temperature range. [ABSTRACT FROM AUTHOR]

(1− x )(Ba,Sr)TiO 3 – x ZnAl 2 O 4 ( x =0.00, 0.05, 0.10 and 0.20) composites were prepared by the traditional solid state reaction. The dielectric, tunable and Raman spectroscopy properties are studied. The curie temperature of the composites does not show much difference due to low solubility between BST and ZnAl 2 O 4 . For the composition with x =0.20, its tunability is up to 46.4% (@2 kV/mm), nearly 1.5 times of that of pure BST, and meanwhile its dielectric constant and loss are decreased. The results imply that making non- or little-soluble BST-nonferroelectric composites is a very effective way to keep high tunability and low dielectric constant simultaneously. Raman results confirm that there are some residual polar microregions in (1− x )BST– x ZnAl 2 O 4 composite, and their extrinsic contribution to the dielectric tunability is responsible for a deviation from the ε versus E behavior predicted by Johnson׳s equation. [ABSTRACT FROM AUTHOR]