Rare-earth elements Sm3+-, Pr3+-, Ho3+- and Er3+-doped (K0.5Na0.5)0.974La0.025Nb0.975Bi0.025O3 ceramics (abbreviated as KNLNB-0.1%RE) were prepared by conventional solid-phase sintering method. The structure, transparency, energy storage and photoluminescence properties of the samples are investigated. All ceramics have the pseudo-cubic phase structure without the impurity phase at room temperature. KNLNB-0.1%RE ceramics exhibit excellent optical transmittance, with KNLNB-0.1%Ho achieving 71.8% transmittance in the visible wavelength range (780nm) and largest effective energy storage density of 1.45J/cm3. In our experiments, rare-earth-doped KNLNB ceramics exhibit photoluminescence effects. This work facilitates the development of transparent energy storage ceramics with fluorescent effects.

Electrocaloric (EC) refrigeration, which employs ferroelectric (FE) ceramics as a working medium, is regarded as a promising green refrigeration technology that could potentially replace vapor-compression refrigeration. One of the principal considerations in EC application is the capacity to attain high EC strength near room temperature. In this work, we investigated the EC effect in Sm/Mn co-doped BaTiO3 [(Ba1?1.5xSmx)(Ti0.99Mn0.01)O3] ceramics. As the smallest trivalent ion that can totally occupy the A site, Sm3+ is not only capable of shifting the Curie temperature but also of optimizing the EC effect. Furthermore, the introduction of the Mn element into the matrix results in the formation of defect dipoles, which also serves to enhance the EC performance. Therefore, large EC strengths of ΔT∕ΔE=0.49KmmkV?1 (@51°C), 0.34KmmkV?1 (@39°C) and 0.21KmmkV?1 (@30°C) were, respectively, achieved in x=0.05–0.07 ceramics, demonstrating the potential for future refrigeration applications.

As a newly emerging catalysis, tribocatalysis is receiving more and more attention with regard to the criteria to fabricate or choose materials as catalysts for it. In this study, two different commercial silicon (Si) powders, Si30 and Si300, were adopted as catalysts in tribocatalytic degradation of organic dyes. Only round nanoparticles from 30 to 100nm were observed in Si30, while some highly large and irregular particles, as large as 1000nm × 500nm and with a roughly flat major surface, could be observed in Si300. Stimulated through magnetic stirring using Teflon magnetic rotary disks, as much as 95% of 20 mg/L rhodamine B (RhB) solution and 97% of 20 mg/L methyl orange (MO) solution were degraded by Si300 after 3h and 50min, respectively; while only 73% of RhB and 83% of MO were degraded by Si30 after 5h and 4h, respectively. EPR spectra showed that more superoxide and hydroxyl radicals were generated by Si300 under magnetic stirring. It is proposed that in those large particles in Si300, their large flat major surfaces dramatically enhance their absorption of mechanical energy through friction and there are much less lattice defects to hinder electrons and holes from diffusing to the surface, which both results in the contrasting tribocatalytic degradations of organic dyes between Si300 and Si30. These findings reveal a huge difference in tribocatalytic performance among different materials of the same composition.

Ternary piezoelectric ceramics Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 (PIN–PMN–PT) exhibit excellent temperature stability and hold great potential for high-frequency and high-power applications. However, its piezoelectric performance is much lower than that of the famous binary Pb(Mg1∕3Nb2∕3)O3–PbTiO3 (PMN–PT) system. In this work, high-performance 15PIN–50PMN–35PT piezoceramics with piezoelectric coefficient d33 of 700 pC/N, electromechanical coupling coefficient kp of 66% and high Curie temperature TC of 199°C were fabricated. Effect of Samarium (Sm) doping content on the ferroelectric, dielectric, electromechanical and piezoelectric properties and structures of 15PIN–50PMN–35PT piezoelectric ceramics were investigated, and results reveal that increasing the amount of Sm doping leads to a significant decrease of d33, kp, TC and other properties. This phenomenon is different from the previously reported results in Sm-doped binary PMN–PT ceramics. The room temperature and variable temperature phase structure and room temperature microstructure were studied to explain this phenomenon.

The A-site rare earth-doped Bi4Ti3O12 (BTO) has been highly interested in nonvolatile ferroelectric random memory devices, piezoelectric devices, electro-optical devices, capacitors, sensors, transducers, etc., due to its low coercive field and superior fatigue resistance properties. However, single B-site doping has not received corresponding attention. In this work, BTO and Bi4Ti3.9Sn0.1O12 (BTS) thin films were prepared by sol–gel method, in which the doping of Sn effectively restrained the grain growth and decreased the grain size, as well as diminished the formation of oxygen vacancies and enhanced the breakdown field. This leads to a significant enhancement of the ferroelectric properties of the BTO films. The final BTS films exhibit excellent saturation P–E loops with a remnant polarization (2Pr) of 94.4μC/cm2 and a coercive field (2Ec) of 0.69MV/cm at a maximum electric field of 2.8MV/cm. The ferroelectric fatigue and dielectric properties of BTS film were also characterized. The results suggest that doping of Sn at B-site can effectively improve the breakdown strength and enhance the ferroelectric properties of the BTO film.

With the rapid development of electronic integration technology, highly integrated chips are in urgent need of packaging materials that are thermally matched to printed circuit boards. Here, Zn1?xCoxAl2O4 (ZCAO, x= 0.00–0.20) ceramics are synthesized using the solid-state reaction method. The phase composition, microstructure, microwave dielectric properties and CTE of Zn2+ in the ZnAl2O4 ceramic substituted by Co2+ are systematically revealed. An appropriate amount of Co2+ substitution promotes a more homogeneous grain growth to form a dense microstructure. The average grain size, bulk density and relative density of ZCAO (x=0.10) ceramic are 1.59μm, 4.472g/cm3 and 97.4%, respectively. The optimal microwave dielectric properties (εr=8.2, Q×f=100,701GHz, τf=?66ppm/°C) of the ZCAO (x=0.10) ceramic sintered at 1450°C are achieved. More importantly, the ZCAO (x = 0.10) possesses a CTE = 11.59ppm/°C that is nearly thermally matched to the printed circuit boards (PCB, CTEPCB = 12ppm/°C). This ceramic has great potential for application in the electronic packaging of PCB devices.

We conducted a study on Mn doping in 67Pb (Mg1∕3Nb2∕3)O3-33PbTiO3(67PMN-33PT), which is a ferroelectric material exhibiting a morphotropic phase boundary (MPB). The samples were doped with MnO2 at mass ratios ranging from 0.5 to 5.0wt.% and subsequently sintered at temperatures ranging from 1200 to 1260°C. Experimental analysis of electrical properties was performed within the temperature range of ?80–200°C. Electron paramagnetic resonance (EPR) testing was conducted on these samples to investigate Mn solubility in PMN-PT ceramics and their existence in different valence states. The results indicate that at a doping ratio of 0.5wt.% and sintering temperature of 1220–1240°C, Mn ions achieved a homogeneous dispersion within the crystal lattice, leading to the enhanced electromechanical Qm factor (510) and the reduced dielectric loss tan δ to minimum (0.30%) compared to the no doping Mn, however, as the Mn ions dopant content increase higher than 1.0wt.% and sintering temperatures 1200–1260°, the unexpected results have been observed that both Qm and tan δ are enhanced to about 1200, 0.87 up to 1.5wt.% MnO2, and then, Qm decreases to 510, but tan δ increases to 3.78% for 5 wt.% MnO2. The machinal Qm and dielectric loss can be understood by the (Mn-Vo) defect dipoles in lattice, domain wall and grain-bounary, together with the increasing of the MnO2, Mn2O3 or their mixed phase of Mn3O4 in the grain boundary.

Rare earth-doped ferroelectric (FE) ceramics have attracted much attention due to their great potential application for novel multifunctional optical-electro devices. This study successfully devised and fabricated tungsten bronze Sr2?xSmxAg0.2 Na0.8Nb5?xZrxO15 ceramics, demonstrating exceptional energy storage and luminescent properties suitable for multifunctional capacitors. Effects of co-doping Sm3+ and Zr4+ in A and B sites on the phases structure, FE, energy storage and photoluminescence properties of Sr2?xSmxAg0.2Na0.8Nb5?xZrxO15 ceramics were systematically investigated. Through employing various collaborative optimization strategies, encompassing the refinement of ceramic grains, the induction of nanodomain generation and the incorporation of large bandgap components, enhancement of breakdown strength and regulation of constructing relaxor FEs were achieved. Encouragingly, the high-performance multifunctional materials with remarkable recoverable energy storage metrics (Wrec～ 3.72J/cm3, η～ 82.7%), brilliant red-orange light emission and distinguished frequency and temperature stabilities within specific ranges were obtained in Sr1.7Sm0.3Ag0.2Na0.8Nb4.7Zr0.3O15 ceramics. Besides, the multifunctional ceramics demonstrated a high-power density (68.1MW/cm3), a substantial current density (908.1A/cm2) and a fast discharge time (51ns) at 190kV/cm. These findings suggest that the designed Sr2?xSmxAg0.2Na0.8Nb5?xZrxO15 ceramics hold promise as candidate materials for dielectric capacitors.

Solid solutions (SS) with a quasi-binary cross-section of a four-component system of the composition (1?x)(Na0.5K0.5)NbO3–xPb(Ti0.5Zr0.5)O3, based on compositions with fundamentally different physical responses (Na, K)NbO3 (KNN), Pb(Ti, Zr)O3 (PZT), have been prepared by a two-stage solid-phase synthesis followed by sintering using conventional ceramic technology. The influence of thermal cycling on the dielectric properties of ceramic SS with x=0.00,…,1.00 has been studied. It has been shown that thermally induced fatigue does not have a significant effect on the Curie temperature and the diffusing of the phase transition (PT) of SS containing only extreme components. It has been found that when the concentration of PZT in the studied system is varied, the ε′/ε0(T) dependencies take on a form characteristic of ferroelectrics with a diffuse PT. When the repolarisation cycles are varied, the diffusing parameter and the Curie and Burns temperatures show a wave-like behavior. The observed effects are explained by the interaction of different defect types. A conclusion is drawn on the possible practical applications of the studied SS.

By X-ray diffraction and dielectric spectroscopy, the crystal structure, phase composition, and properties of Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/SrRuO3/MgO and Ba2NdFeNb4O15/Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO multilayer heterostructures were studied. The heterostructures were manufactured under identical conditions but differing in the layer deposition sequence. It is shown that the orientation domains are formed in each Ba2NdFeNb4O15 (BNFN) and Sr0.6Ba0.4Nb2O6 (SBN) layers. BNFN and SBN layers have tetragonal unit cells with tensile out-of-plane strain and compression in-plane strain. At T=?100…100°C both heterostructures are characterized by fairly high relative permittivity values. The reasons for the revealed regularities are discussed.

The primary aim of the current research is to explore the impact of yttrium-doping in barium stannate titanate (Ba1?1.5xYxTi1?zSnzO3) to investigate the variation in its structural and electrical properties. The specimens were synthesized using a solid-state method, wherein the precursors were heated together until they reacted to form the desired compounds. Subsequently, X-ray diffractometric analysis was employed to confirm the crystallographic phases. Archimedes’ method was used to determine the density of the material. An Electron Paramagnetic Resonance (EPR) study was conducted to examine the nature of defect centers and impurity ions within the synthesized ceramics. Furthermore, the impact of yttrium (Y) substitution on the system’s morphology and grain growth was evaluated through SEM micrographs. Selective compositions were found with enhanced dielectric properties of barium titanate ceramic, exhibiting a dielectric constant of 9816 at the transition point. The highest value among all studied samples had a clear indication of DC conductivity. Piezoelectric coefficient (d33) and P-E hysteresis loops were also investigated for these samples, indicating potential applications in electronic devices for the modified material’s improved ferroelectric properties.

In this paper, we present the electric field controllable diffractive optical elements in strontium–barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of optical beam with orbital angular momentum. The required domain pattern was created in the sample with initial domain structure by electric field application using the photolithographically defined liquid electrode. A series of bipolar triangular electric field pulses were applied to the sample for determination of the optimal parameters for complete polarization switching under the electrode. The stable tailored domain pattern of the spiral shape was created by the application of the unipolar pulse of a special shape. The complete switching under the electrode and partial switching under the photoresist layer have been revealed. The imaging by Cherenkov-type second harmonic generation microscopy confirmed that the created domain structure reaches the opposite polar surface. The imaging of the diffraction pattern of the laser beam passing through a voltage-biased DOE confirmed the formation of the beam with orbital angular momentum. The half-wave voltages of 237V and 302V for wavelength 632.8nm and 532nm, respectively, for 2-mm-thick sample were measured. The obtained knowledge can be used for the development of domain engineering methods in strontium–barium niobate single crystals for the creation of tailored domain structures for manufacturing of electric field controllable diffractive optical elements.

This work investigated the structure and dielectric behavior of precursor-derived spark plasma sintered (SPS) hafnium dioxide (HfO2). X-ray diffractograms confirmed the presence of monoclinic HfO2 (m-HfO2) and scanning electron micrographs revealed micron/nanosized grains and grain boundaries in SPS m-HfO2. The theoretical density of ceramics is 94%, and the porosity is very low. In the temperature interval of 25–200°C, the real part of the permittivity (ε′) is almost frequency- and temperature-independent and the ε′ value is about 21 in the frequency range 102?106Hz. ε′ of SPS ceramics is higher than that of traditionally sintered HfO2 ceramics. At temperatures above 225°C, there is a sharp increase in the permittivity and loss at low measuring frequencies. In order to comprehend the underlying conduction mechanisms, an analysis of the dispersion dependences of the dielectric response was undertaken. High permittivity values were attributed to the space charge polarization mechanism occurring at grain boundaries due to the thermally activated movement of oxygen vacancies. The DC conductivity of SPS m-HfO2 is thermally activated, and conductivity is determined by oxygen vacancies through hopping mechanism.

Polymer composites are emerging as critical materials for advanced dielectric energy storage due to their excellent flexibility, high dielectric constant (εr), and superior pressure resistance. They are ideal for next-generation devices requiring high power density and fast charge/discharge cycles. Strategic selection of fillers — optimizing their composition, structure, and surface properties within the polymer matrix — significantly enhances composite performance. This review examines recent advances in dielectric polymer composites, emphasizing the critical challenge of filler dispersion, which directly impacts homogeneity and overall performance. We categorize nanofillers based on size, shape, and material properties and discuss surface modification strategies to mitigate dielectric mismatches between fillers and matrices. We also explore the design of transition layers around nanofillers to improve filler-matrix interactions and enhance dielectric performance. Additionally, the spatial architecture of multilayer films is examined, demonstrating how layer arrangement optimizes electric field distribution and breakdown strength. Finally, we address critical challenges in developing high-performance dielectric polymer composites for capacitors and outline future research directions to improve recoverable energy density, stability, and scalability for commercial applications. This review offers valuable insights for researchers and engineers working to advance dielectric energy storage materials.