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Modified BaTiO3 ceramics that possess high dielectric permittivity and acceptable temperature stability have been widely utilized as multilayer ceramic capacitors (MLCCs) for high‐frequency bypass and power filtering in automotive applications. However, since the increasing demand for high‐capacity and small‐size, high‐permittivity materials that can serve as dielectric layers in MLCCs are urgently required. In this work, we design and fabricate a special BaTiO3‐0.03Mg‐0.02Y‐0.02CaZrO3 ceramic with a high dielectric permittivity of 3000 and the dielectric variation below ±13% in the temperature range of ‐55–150°C, fulfilling the requirements of X8R capacitors. To achieve these results, we employed grain size engineering and cation doping, using BaTiO3 precursors with a particle size of 240 nm to prepare the BaTiO3‐based ceramics with fine grains, while Mg and Y co‐doping was used for improving the temperature stability due to dielectric dispersion. Utilizing these high‐permittivity BaTiO3‐based materials, we fabricated MLCCs that satisfy the X8R criterion, possessing a high dielectric constant of 2950 and a high breakdown field (410 kV/cm). [ABSTRACT FROM AUTHOR]

Excellent energy storage performance of dielectric capacitors is highly desired in all kinds of energy storage devices. In this study, Sr(Sc0.5Nb0.5)O3 was introduced to enhance the energy storage properties of (Bi0.47La0.03Na0.5)0.94Ba0.06TiO3 (BLNBT) ceramics. All ceramic samples were sintered densely, and the phase structure, microstructure, dielectric and ferroelectric properties were then systematically investigated. Two distinct dielectric anomaly peaks, which are detected from the dielectric properties as a function of temperature, suggest not only a phase transition, but also indicate typical relaxor features. The breakdown strength is significantly improved, and the polarization versus electric field hysteresis loops become slim with the increasing content of SSN. The optimum energy storage performance is achieved in 0.85BLNBT–0.15SSN ceramic with the recoverable energy density of 1.83 J/cm3 and energy efficiency of 82.32% under a moderate electric field of 185 kV/cm. The excellent energy storage performance of 0.85BLNBT–0.15SSN ceramic makes it a promising candidate material for advanced pulsed power capacitors. [ABSTRACT FROM AUTHOR]

Abstract The (Nb + In) co-doped rutile TiO 2 ceramics were synthesized by spark plasma sintering (SPS) and traditional solid-state sintering (TS) techniques, respectively. Highly-density co-doped rutile TiO 2 ceramics are prepared with the SPS method by 20 min, whereas it takes nearly 30 h with the TS method. It is observed that SPS ceramics showed smaller and uniform grain size, and better densification than TS counterparts. Both sets of the co-doped TiO 2 ceramics showed single rutile phase according to X-ray diffraction (XRD) results. X-ray photoelectron spectroscopy (XPS) is adopted to detect and compare the element-valence-state of both sets of the co-doped TiO 2 ceramics. The dielectric response, impedance spectroscopy (IS), and the effects of annealing treatment are systematically investigated, which could not only be helpful for optimizing their dielectric properties, but also shed the light on the colossal dielectric mechanism. Highlights • The sintering techniques is the most critical factor for CP in co-doped TiO 2 systems. • The existence of Ti3+ ions is a preliminary requirement for CP. • This paper shed light on the recognition of CP behavior in other metallic oxides. [ABSTRACT FROM AUTHOR]

In order to meet the demand for miniaturized devices, ferroelectric ceramics with micro- or nano-crystal particle size are among the primary needs. In this work, we fabricated 5 mol.% cerium-doped BaTiO (CBTO) nanofibers by using sol-gel combined with electrospinning. The mechanism of doping has been investigated in detail by multiple methods. In addition, the dielectric and ferroelectric properties of the obtained CBTO ceramics fabricated by these nanofibers were investigated. Their phase transition temperature shifted to a lower temperature due to the cerium dopant and size effects. An obvious decrease of ferroelectricity of the ceramics was observed, possibly due to the existence of polar nano-regions and cerium ions. The lower curie temperature of CBTO ceramics makes it possible for over-temperature protection applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Bi2O3 addition could promote the grain growth in Sr0.4Ba0.6Nb2O6 ceramics. [•] Doping Bi2O3 could improve the dielectric constant and lower the dielectric loss. [•] The dielectric characteristics of doping Bi2O3 samples showed relaxation behavior. [•] The P–E hysteresis loops for doping Bi2O3 ceramics became slimmer. [ABSTRACT FROM AUTHOR]

Abstract: A conventional solid-state reaction was used to synthesize (1-x) Sr0.7Ba0.3Nb2O6–xBaTiO3 (0.00≤x≤0.10) ceramics. The phase structure, microstructure, and dielectric and relaxor ferroelectric properties of these ceramics were investigated. Tungsten bronze structure can be observed in ceramics, and addition of BaTiO3 can make the grain size decrease and the porosity increase. The dielectric characteristics show diffuse phase transition phenomena for all samples, which were demonstrated by a linear fit of the modified Curie-Weiss law with γ varying between 1.54 and 1.88. As the BaTiO3 content increases, the transition temperature (T C ) decreases gradually and has a minimum value of 37.53°C at composition x=0.06, and the maximum dielectric constant (ε max ) increases gradually from 66 to 3309 and subsequently decreases to 1625 at x=0.10. In addition, the relaxor ferroelectric properties of these ceramics at x=0.8 are consistent with the Volgel-Fulcher relationship; polarization versus electric field ( P-E ) loops were measured at a different temperature. [Copyright &y& Elsevier]

The new (Nb+In) co-doped TiO 2 ceramics recently stimulated considerable attention due to their colossal permittivity (CP) (~100,000). In this research, the 3 mol% (Nb+In) co-doped TiO 2 ceramics were synthesized by an standard solid-state reaction method. Phase structure was studied by XRD and Raman, which showed that all samples were in pure rutile phase. The elements distribution was tested by the SEM–EDS, indicating that the Nb and In ions were homogeneously distributed in the grain and grain boundary. Dielectric properties and I – V behavior analysis demonstrated that the ceramics may compose of semiconducting grains and insulating grain boundaries. The existence of CP and nonlinear I – V behavior in sample had been explained by an internal barrier layer capacitance (IBLC) model, which consists of n-type semiconductor grains and insulating grain boundaries. [ABSTRACT FROM AUTHOR]

Abstract: Lead-free perovskite type (Ba0.94Bi0.06)(Ti0.94Cr0.06)O3 (BBTC) ceramics have been prepared by the conventional mixed oxide method. The XRD results showed that BBTC ceramics have single phase tetragonal symmetry with space group P4mm. Dielectric studies exhibited a diffuse phase transition characterized by a strong temperature and frequency dispersion of permittivity. The quantitative characterization based on empirical parameters (ΔT m , γ, ΔT relax , and ΔT dif ) confirmed its relaxor nature. The origin of relax ferroelectric behavior is caused by the polar nanoclusters, which were arose due to the heterovalent substitutions of Bi3+ and Cr3+ at Ba2+ and Ti4+ sites. The P–E loops obtained at the temperature quite above T m supported the diffuse phase transition behavior of the samples. [Copyright &y& Elsevier]