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Effects of Eu doping at the A site on the magnetic properties of the perovskite manganite La0.8-xEuxSr0.2MnO3(x = 0 and 0.05)polycrystalline samples were investigated in this paper. The polycrystalline La0.8-xEuxSr0.2MnO3 (x = 0,0.05)samples were synthesized using a traditional solid-phase reaction method. X-ray diffraction (XRD) analysis of the polycrystalline samples did not indicate any impurities, confirming that the samples are single phase. The magnetization vs. temperature curve (M-T), as well as the magnetization vs. magnetic field curves (M-H) of the two samples, show that both synthesized structures are paramagnetic in the high-temperature region, while near the Curie temperature (Tc), the material is ferromagnetic. The Tc of both samples, La0.8-xEuxSr0.2MnO3 with x = 0 and the Eu3+-doped sample with x = 0.05, increased to 283 K and 284 K, respectively. The hysteresis loops of the samples show insignificant coercive force and no remanence. The inverse magnetic susceptibility vs. temperature curves (χ−1-T, χ−1 = H/M) indicate that the Griffiths phase temperature remains unchanged, while the Curie temperature decreases. The trends confirm that $${Eu}^{3+}$$ doping changed the ferromagnetic coupling of the system. The average field model provides a good fit for the critical parameter response of both the parent and the doped synthesized material. At an applied field of 7 T, the change in magnetic entropy of the doped sample reaches its highest value at 4.19 J/kg·K, and the refrigeration efficiency is 445 J/kg. Our results show that the newly synthesized polycrystalline samples could be used as magnetic refrigeration materials.

Pb0.91Ba0.06La0.02(Zr0.95−xSnxTi0.05)O3 (PBLZST, x = 0.325, 0.35, 0.375, 0.4) thick films are prepared by solid-state reaction method and flow-casting method. Trace Ba2+ content is introduced to PLZST which is effective in narrowing the hysteresis loop, lowering the Curie temperature point, and improving the fatigue characteristics. Besides that, Zr:Sn ratios are adjusted to study its influence on the material’s energy storage characteristics. PBLZST ceramics with different Zr:Sn ratios are all in tetragonal perovskite structure. The increase of Sn4+ content promotes miniaturization of crystal grain and contributes to stability of antiferroelectric phase, together with enhances the phase transition field strength and breakdown field strength of PBLZST ceramics. The PBLZST ceramic has high energy storage efficiency, which is more than 80%. The maximum effective energy storage density of PBLZST ceramics at 1.94 J/cm3 is obtained when x = 0.35, and their energy storage efficiency is 81.9%, which confirms that they are the potential materials in the pulse energy storage components.

(1 − x)BaTiO3–x (Bi2O3, Sm2O3) (BT–BS, x = 0.1, 0.15, 0.2, 0.25, 0.3) ceramics were prepared by traditional solid phase sintering method. The effects of structure, temperature and frequency on dielectric tunability, ferroelectric relaxation characteristics and dielectric loss were analyzed. Phase analysis by XRD showed that the main crystal phase was BaTiO3 perovskite structure, in addition to the second phase of Bi7.68Ti0.32O12.16 was also generated. The surface morphology was analyzed by SEM, it was found that the generation of second phase and the porosity decreased with the increase of BS content. At the same time, the increase of Sm3+ promoted the growth of crystal particles. The dielectric constant-temperature curve gradually became flat, which indicated that the relaxation characteristics of the ferroelectric ceramic gradually appear. The Curie temperature point gradually decreased with the doping of the BS. The relationship between dielectric loss and temperature showed that the dielectric loss increased when the temperature over 150 °C. This is mainly related to relaxation polarization at high temperature. Under the action of DC applied electric field and room temperature, dielectric loss and dielectric constant decreased with the increase of BS content. Meanwhile, dielectric tunability was improved when composite phase appeared. The maximum dielectric tunability (E = 50 kV/cm, 10 kHz) was 58.4% at x = 0.25.

The dielectric and energy-storage properties of (Pb0.97−xSrxLa0.02)(Zr0.675Sn0.285Ti0.04)O3 (x = 0, 0.005, 0.01, 0.015) bulk ceramics and thick films were investigated. All samples are orthorhombic perovskite antiferroelectric phase and have dielectric temperature relaxation property. Sr-dopant can improve the stability of the antiferroelectric phase and increase the phase transition field, but cause a decrease in dielectric constant. Thick films have a higher maximum tolerable external electric field strength than bulk ceramics. Compared with undoped thick film, the forward phase transition field and the backward phase transition field of the 1.5% doped thick film increased by 32% and 27%, respectively. The maximum polarization of the 1.5% doped thick film is decreased by 17%. The largest recoverable energy-storage density was obtained in thick film with 1% Sr doping. The largest recoverable energy-storage density is 2.77 J/cm3, which is 9.4% higher than the undoped thick film ceramic and 477% higher than the bulk ceramic with 1% Sr doping. The high energy storage density indicates that the obtained thick film is promising for pulsed power capacitors.

Barium strontium titanate (BaxSr1–xTiO3, BST) thin films have large dielectric constant, low dielectric loss, especially the high dielectric tunability, which make them prospective candidates for microwave tunable applications. Resent developments in BST thin films by doping modification are reviewed. The A-site doping, B-site doping, and both sites codoping modifications are summarized and analyzed, respectively. The comparison of dielectric properties and microstructure of the BST thin films with different sites doping modifications is critically analyzed. The single A-site or B-site doping modification cannot obtain the BST thin films with balanced enhancement of the dielectric properties. However, the different elements codoping in both A-site and B-site of BST thin films is demonstrated to be an effective method to achieve balanced dielectric property optimization.

In this paper, 0.8BaTiO3–0.2BiYO3 was prepared by traditional process. The samples were sintered with tradition method and two-step sintering method, respectively. The effects of different sintering conditions on grain size, density and dielectric properties were investigated. When the samples heated to 1100 °C, cooled to 1000 °C and held for 20 h, the relative density and the recoverable energy density of the samples reached the maximum (0.379 J/cm3 with energy efficiency of 72.8%).

(1 − x)(Pb0.97La0.02)(Zr0.5Sn0.44Ti0.06)–xBiYO3 ((1 − x)PLZST–xBYO), with x = 0.0–0.5, have been fabricated by the conventional solid-state reaction process. The phase evolution, microstructure, dielectric and energy storage properties have been investigated in detail. According to the XRD study, a secondary phase was found at room-temperature. The secondary phase was gradually increased with increasing x. The microstructure further revealed that the BYO doping leads to an increase in secondary phase. The EDS analysis revealed that Bi ions and Y ions are mainly substituted for A-site in the perovskite structure. As a result, the maximum value of energy storage density is 0.8 J/cm3, which is 2.66 times as high as that of pure PLZST ceramics.

NanoTiO2/glass composite was potential in pulse power capacitors applications. The glass addition could deduce the porosity, suppress the grain size and improve the BDS of the composite, simultaneously. In this study, the composite was densified successfully by the method of repeating the pre-sintering and ball milling procedure multiple times, which could improve the density and the breakdown strength (BDS) of the composite significantly. When the ratio of TiO2 with 15 % glass addition and the number of pre-sintering times was 4, the energy density achieved the highest energy density 1.41 J/cm3. The method was very simple and inexpensive to compatible with multilayer ceramic capacitor, comparing to sol–gel method and other methods.

In this paper, the composites of the TiO2–CaO–MgO–Al2O3–SiO2 glass-ceramic were successfully produced by the method of Sol–Gel from tetrabutyl titanate as the titanium (Ti) source, which were sintering at 1300 °C for 2 h. The dielectric properties of the composites were studied. The highest energy density reached 1.05 J/cm3 with low loss (

The dielectric properties and microstructures of 0.05 mol% manganese (Mn)-doped TiO2 with different alkali-free glass (BaO–B2O3–Al2O3–SiO2) contents were investigated. The alkali-free glass which coated Mn-doped TiO2 ceramic powders was prepared by sol–gel method, all samples were sintered at 1100 °C for 6 h. Microstructure observation indicated that the grain size greatly reduced and microstructure uniformity was improved by adding 15 wt% alkali-free glass. The alkali-free glass did not only decrease the dielectric loss (

In this search, the nanocomposite of the rutile nano TiO2 and alkali-free glass (CaO–MgO–Al2O3–SiO2) were successfully produced by the method of sol–gel, which were sintered at 1200 °C for 2 h. The dielectric properties of the composites were studied. The permittivity of the composite with 15 % alkali-free glass addition is 114, while the breakdown voltage is 52.2 kV/mm and the energy density reaches 1.08 J/cm3 with low loss (

Glass/semiconductor nanocomposites have a high dielectric constant and voltage resistant, which has potential as dielectric material for multilayer ceramic capacitor and low frequency capacitor. This article reported a glass/semiconductor nanocomposite of coating ZnO nano powders by a kind of PbO–B2O3 glass by spray-drying method. We used lead acetate [(CH3COO)2Pb·3H2O] and boric acid (H3BO3) which were water-solubility for raw materials. The size of semiconductor powders were between 200 and 300 nm. This method could make the ZnO coating by glass insulated. In addition, ZnO coated by 40 wt% glass can obtain a high dielectric constant of 150 and the loss below 2 %. This method was very simple and easy to control. Semiconductor-glass was another way to obtain high dielectric constant and low loss.

Ba0.6Sr0.4TiO3 ferroelectric thin films were deposited on Pt/Ti/LaAlO3 (100) substrates by RF magnetron sputtering system. This paper focused on X-ray diffraction (XRD) analyses of Ba0.6Sr0.4TiO3 thin films on single-crystal LaAlO3 (LAO) substrates by three aspects research. Triple-axis XRD was utilized to investigate the mosaic defects of single-crystal LAO substrate. Both the out-of-plane grazing incidence mapping and ω-scan techniques were applied to research the crystallographic oriented growth of polycrystalline Ba0.6Sr0.4TiO3 thin films. X-ray Φ-scans and pole figures were used to assess the orientation relationship between the film and substrate.

Thin film NTCR (negative temperature coefficient resistance), based on Mn–Co–Ni oxide, was prepared by reactive RF magnetron sputtering with various sputtering power density (0.95–3.82 W/cm2). The crystalline structure and surface morphology of the NTC thin film were analyzed by XRD and AFM. The NTC characteristics, as a function of sputtering power density, were investigated. The values of B, α 25 and R 25 were in the range of 3,740–3,847 K, −4.328 to −4.207 %/K and 8.7–2,082.5 KΩ, respectively. With the increasing power density, the standard resistance (R 25 ) decreased and the consistency of R25 increased. Thin film NTCR with stable B value (3,740 K), low R 25 (104 Ω) and excellent consistency could be fabricated in mass production with about 3.82 W/cm2 sputtering power density.

Ba0.6Sr0.4TiO3 (short for BST) thin films were prepared by RF magnetron sputtering. By adjusting annealing conditions, the BST thin films with different grain sizes were obtained. The microstructures of BST thin films were studied by X-ray diffraction (XRD), atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM). It is found that there are two critical sizes in BST thin films in relation to grain sizes. The crystalline critical size from amorphous to crystalline is about 10 nm. The ferroelectric critical size from cubic (paraelectric) to tetragonal (ferroelectric) is about 20 nm.

Ba(Zr0.2Ti0.8)O3 (BZT) thin films were deposited on Pt/Ti/LaAlO3 (001) substrates by radio-frequency magnetron sputtering at different O2/Ar mixing ratios. As the O2/Ar ratio increased (1/4–4), the preferred orientation evolved from (00l) to (111). The grain size and the surface roughness increased, and the ferroelectric properties improved with increasing O2/Ar ratio. The BZT thin films deposited under oxygen-rich atmosphere (O2/Ar = 4) had larger dielectric constant (443) and tunability (44%), while the BZT films deposited under argon-rich atmosphere (O2/Ar = 1/4) had a lower loss tangent (0.016).

The crystalline structure and dielectric properties of BaZr x Ti1−x O3 ceramics with x = 0.05, 0.10, 0.15, and 0.20 were investigated. As zirconium increased, the a-axis lattice constant gradually increased, however, the c-axis lattice constant and c/a ratio gradually decreased. When x = 0.20, the crystal structures of the BZT ceramics are very close to cubic, different from the tetragonal structure when x

Linear and nonlinear optical properties of (Pb,La)(Zr,Ti)O-3 (PLZT) ferroelectric thin films were presented in this paper. The PLZT ferroelectric thin films have been in situ grown on quartz substrates by radio-frequency (RF) magnetron sputtering at 650 degrees C. Their crystalline structure and surface morphologies were examined by X-ray diffraction and atomic force microscopy, respectively. It can be found that the PLZT thin films exhibit well-crystallized perovskite structure and good surface morphology. The fundamental optical constants (the band gap energy, linear refractive index, and linear absorption coefficient) were obtained through the optical transmittance measurements. A Z-scan technique was used to investigate the optical nonlinearity of the PLZT thin films on quartz substrates. The films display the strong third-order nonlinear optical effect. A large and negative nonlinear refractive index n(2) is determined to be 1.21 x 10(-6) esu for the PLZT thin films. All results show that the PLZT ferroelectric thin films have potential applications in optical limiting, switching, and modulated-type optical devices.

The effect of annealing on leakage current characteristics of Pt/Ba0.6Sr0.4TiO3/Pt ferroelectric thin-film capacitors was investigated at the temperature range from 273 K to 393 K. The results show that the depletion layer width of the as-deposited BST film is about 3–5 times greater than that of the annealed film. For as-deposited samples, the Schottky barrier height increases with increasing temperature and voltage. However, for annealed samples, the Schottky barrier height linearly decreases with increasing voltage and is almost independent upon temperature.

Ferroelectric (Pb0.92La0.08)(Zr0.65Ti0.35)O3 (PLZT) films have been prepared on Pt/Ti/SiO2/Si and fused quartz substrates using radio-frequency (rf) magnetron sputtering at a deposition temperature of 650°C. X-ray diffraction analysis shows that the PLZT thin films on platinized silicon are polycrystalline with (100)-preferential orientation. A Al/PLZT/Pt capacitor has been fabricated and it shows that the films have excellent ferroelectric character, with saturation polarization (P s), remanent polarization (P r) and coercive field (E c) of 32.8μC/cm2, 24.3μC/cm2 and 142 kV/cm, respectively. The PLZT thin films exhibit good insulating property and the leakage current density of the films on platinized silicon is only about 0.86 × 10−7 A/cm2 at 200 kV/cm. By the optical transmission spectra measurements, the energy gap (E g) of the PLZT films on fused quartz is found to be about 3.54 eV. The optical constants (n and k) of the films in the wavelength range of 250–900 nm are obtained by a Filmetrics F20 reflectance spectrometer.