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Bi0.47Na0.47Ba0.06Ti1-x(Ni1/3Nb2/3)xO3 ceramics (abbreviated as BNBT1-x(NN)x, x = 0, 0.01, 0.03 and 0.05) were synthesized by solid-state combustion. The effect of x on the phase formation, microstructure and electrical properties of BNBT1-x(NN)x ceramics was examined. The XRD pattern indicated the coexistence of rhombohedral and tetragonal phases in all the specimens. Moreover, Rietveld refinement confirmed that the tetragonal phase increased from 47 to 71% when x increased from 0 to 0.05. The morphology of BNBT1-x(NN)x ceramics was observed by SEM and the ceramics grains showed polygonal shapes and the grain growth tended to be anisotropic. With (NiNb)4+ substitution, the average grain sized decreased rapidly from 1.7 to 1.0 µm and the grain size distribution was narrower as the amount of (NiNb)4+ increased. The density, remnant polarization (Pr) and coercive field (Ec) rapidly decreased with increasing x. A significant decrease in the ferroelectric properties was caused by the increasing tetragonal phase. [ABSTRACT FROM AUTHOR]

Lead-free [(Bi0.5Na0.5)0.94Ba0.06]1-xLaxTiO3 (BNBT-xLa) ceramics with x = 0, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 mol.% were synthesized by the solid-state combustion technique with calcination and sintering temperatures of 750 °C and 1150 °C, respectively, for 2 h. The phase formation, microstructure, dielectric, ferroelectric and energy storage properties of the BNBT-xLa ceramics were investigated. The XRD patterns of the powders showed a pure perovskite phase for all samples. The average particle size increased from 298 to 379 nm with increasing x. All ceramics showed coexisting rhombohedral and tetragonal phases. When x rose, the content of the tetragonal phase increased, as validated by the Rietveld refinement method. The average grain size decreased from 1.43 to 0.81 µm when x increased from 0 to 0.05 and then started to increase. The Curie temperature (Td) of the samples shifted to lower temperatures with rising x, owing to an increased tetragonal phase. The maximum dielectric constant (εm), remanent polarization (Pr) and coercive field (Ec) decreased with increasing x. The BNBT-0.05La ceramic exhibited the smallest grain size, and lowest Pr = 0.8 µC/cm2 and Ec = 2.9 kV/cm, with the highest energy storage efficiency (η ∼ 78.31%) and a large effective energy storage density (W ∼ 0.83 J/cm3) measured in an electric field of 80 kV/cm. [ABSTRACT FROM AUTHOR]

Lead-free (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) ceramics with Li+ substitution (KN0.5-xLixNT) and direct (KNNT-xLi) doping at x = 0, 0.01, 0.02, 0.03 and 0.04 mol% were synthesized by the solid-state combustion route. The phase, microstructure, dielectric and ferroelectric properties of the ceramics were examined. The XRD pattern of the ceramics revealed orthorhombic and tetragonal phases in all specimens. The Rietveld refinement procedure showed that increasing either the Li+ substitution or doping levels enhanced the amount of the tetragonal phase. It was found that Li+ doping, either substitutional or additional, enhanced the Curie temperature (TC) by increasing the tetragonal distortion, while the dielectric constant (εC) decreased. The good remanent P-E loops of the KN0.5-xLixNT ceramics were found with x = 0.01 (Pr∼10.89 µC/cm2 and EC∼13.09 kV/cm), while for KNNT-xLi ceramics, it was obtained with x = 0.02 (Pr∼15.65 µC/cm2 and EC∼11.46 kV/cm), which were confirmed by remanent P-E hysteresis measurements. [ABSTRACT FROM AUTHOR]

In this research, the effects of calcination temperature in a range of 1050–1200 °C for 2 h and sintering temperature in a range of 1325-1400 °C for 2 h on phase formation, microstructure and electrical properties of lead-free Ba0.9Ca0.1TiO3 (BCT) ceramics fabricated via the solid-state combustion technique were investigated. For the XRD result, all the ceramics exhibited a coexisting phase between tetragonal and orthorhombic. The ceramic grain size tended to increase with increase of the sintering temperature. For BCT ceramic produced by the optimum sintering temperature (1375 °C for 2 h), the dielectric, ferroelectric and piezoelectric properties of εC=7393, Pr=7.60 μC/cm2,EC=5.99 kV/cm and d33=158 pC/N, respectively, were obtained. [ABSTRACT FROM AUTHOR]

Bi0.5(Na0.68K0.22Li0.10)0.5Ti1−xCoxO3 lead-free perovskite ceramics (BNKLT−xCo, x = 0, 0.005, 0.010, 0.015 and 0.020) were fabricated via the solid-state combustion technique. A small-amount of Co2+ ion substitution into Ti-sites led to modification of the phase formation, microstructure, electrical and magnetic properties of BNKLT ceramics. Coexisting rhombohedral and tetragonal phases were observed in all samples using the X-ray diffraction (XRD) technique. The Rietveld refinement revealed that the rhombohedral phase increased from 39% to 88% when x increased from 0 to 0.020. The average grain size increased when x increased. With increasing x, more oxygen vacancies were generated, leading to asymmetry in the bipolar strain (S−E) hysteresis loops. For the composition of x = 0.010, a high dielectric constant (εm) of 5384 and a large strain (Smax) of 0.23% with the normalized strain (d*33) of 460 pm·V−1 were achieved. The BNKLT−0Co ceramic showed diamagnetic behavior but all of the BNKLT−xCo ceramics exhibited paramagnetic behavior, measured at 50 K. [ABSTRACT FROM AUTHOR]

Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi1−xNbxO3 (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (Eg). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, Eg, Nyquist plot, and Mott-Schottky analyses. [ABSTRACT FROM AUTHOR]

This research studied the effect of MnO2 substitution on the phase formation, microstructure and electrical properties of (Ba0.97Ca0.03)(Ti0.94-xMnxSn0.06)O3 (BCTMS with x = 0, 0.005, 0.010, 0.015, and 0.020 mol%) lead-free piezoelectric ceramics. The BCTMS ceramics were fabricated by the solid-state combustion technique. The powders and green pellets were calcined and sintered at 1100 °C for 4 h and 1400 °C for 2 h, respectively. The XRD patterns of all BCTMS ceramics exhibited a single perovskite structure with the coexisting orthorhombic and tetragonal phases, where the tetragonal phase increased and the orthorhombic decreases with increasing x. The average grain size decreased from 35 to 13 µm with increasing x. The dielectric constants at room temperature (εr) and at the Curie temperature (εC), density, remanent polarization (Pr), and piezoelectric coefficient (d33) decreased as x increased. The changes in the crystal structure and microstructure affected electrical properties. [ABSTRACT FROM AUTHOR]

In this work, the effect of La2O3 doping (x = 0–1.6 wt%) on the phase formation, microstructure and electrical properties of (K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3 (KNLNTS) ceramics was investigated. These samples were fabricated by the solid-state combustion method using glycine as fuel. The KNLNTS ceramics doping with La2O3 powders were calcined and sintered at 750 °C and between 1100 and 1200 °C, respectively, for 2 h. From the X-ray diffraction (XRD) results, the ceramics had a pure perovskite phase with coexisting orthorhombic and tetragonal phases in all samples. The Rietveld refinement analysis suggested that the tetragonality increased with increasing La2O3 doping. The grain morphology of the ceramics exhibited a rather square shape. The average grain size and the density of the ceramics tended to decrease from 1.5 to 0.7 µm and 4.71 to 4.56 g/cm3, respectively, when increasing La2O3 contents from 0 to 1.6 wt%. The dielectric behavior of the ceramics degenerated with La2O3 doping. A decrease in the leakage current and saturated hysteresis loops were observed in the samples doped with La2O3 ≥ 0.8 wt%. [ABSTRACT FROM AUTHOR]

This research studied the effect of W4+ substitution on the phase formation, microstructure and electrical properties of (Ba0.97Ca0.03)(Ti0.94-x/2Sn0.06-x/2Wx)O3 (BCTSW) ceramics with x = 0, 0.005, 0.010, 0.015 and 0.020 mol%. The BCTSW ceramics were synthesized by the solid-state combustion technique, using glycine as fuel. The powders and green pellets of BCTWS were calcined and sintered at 1100 °C for 4 h and 1400 °C for 2 h, respectively. A pure perovskite phase with coexisting orthorhombic and tetragonal phases were observed for all samples. The content of the tetragonal phase increased when x rose, as verified by the Rietveld refinement procedure. The average grain size and the measured density of the samples tended to decrease from 35 ± 0.56 to 1.9 ± 0.12 µm and 5.59 to 4.88 g/cm3, respectively, when x increased. The dielectric behavior of the ceramics strongly degenerated upon W4+ substitution. The undoped BCTS ceramic showed a well-saturated P-E hysteresis loop. With W4+ substitution, the samples' P-E loops became unsaturated and a leakage current was created. [ABSTRACT FROM AUTHOR]

Lead-free [(0.76-x)Bi0.5Na0.5TiO3–0.24SrTiO3–x(K0.5Na0.5)NbO3; BNT-ST-KNN] ceramics with x = 0, 0.03, 0.05, 0.07, 0.10, 0.15 wt.% were synthesized by using a solid-state reaction method. The effect of x content on phase, microstructure electrical and energy density properties was investigated. The samples were analyzed by X-ray diffraction (XRD) and the XRD patterns were fitted using the Rietveld refinement. The grain growth is obviously inhibited and smaller grains are formed in the ceramic samples at a high concentration of x. Dielectric study confirmed relax or nature with a drastic decrease of Tmax with the increase of x content in BNT-ST-KNN system. The maximum density (ρ = 5.42 ± 0.13 g/cm3), highest dielectric constant (εr=3300) with tanδ∼0.05, high recoverable energy storage density (Wrec=0.16 J/cm3) with energy storage efficiency of (η = 64) were obtained in x = 0.03 wt.% ceramic samples, which suggested its usefulness for energy-storage capacitor applications. [ABSTRACT FROM AUTHOR]

Lead-free 0.81(Bi0.5Na0.5TiO3)-0.18(Bi0.5K0.5TiO3)-0.01(K0.5Na0.5NbO3) (BNT-BKT-KNN) ceramics doped with Fe2O3 (0–0.8 wt%), were prepared via the solid-state combustion method using glycine as fuel. The effect of Fe2O3 doping on the phase formation, microstructure, dielectric and magnetic properties of the ceramics was investigated. The XRD and Raman spectra of all ceramics indicated a pure perovskite structure with coexisting rhombohedral and tetragonal phases. The microstructure showed a polygon grain shape for all compositions. The average grain size and density of the ceramics tended to increase from 0.38 to 0.77 μm and 5.56 to 5.80 g/cm3 with increasing x content. The ceramics with 0.4 wt% Fe2O3 doping showed the highest maximum dielectric constant (εm=5424) which corresponded to the microstructure and density results. Without Fe2O3 doping, the BNT-BKT-KNN ceramic showed diamagnetic behavior, whereas all of the Fe2O3 doped ceramics exhibited paramagnetic behavior, measured at a temperature of 25°C. [ABSTRACT FROM AUTHOR]

In this study, the effect of Al2O3 nano-particles on Ba(Zr0.95Ti0.05)O3 or BZT ceramics prepared by mixed oxide method with various amount of Al2O3 were investigated. The BZT powders were calcined at 1100 °C for 3 h with heating rate of 5 °C/min. The sintering procedure of BZT + x wt.% Al2O3 nano-particles (x = 0.3, 0.7 and 1.0) was carried out at 1300 °C for 2 h with heating rate of 5 °C/min. The results showed that, all XRD patterns of BZT + x wt.% Al2O3 nano-particles ceramics could be matched with a JCPDS data file number 06-0399. The BZT + 0.7 wt.% Al2O3 nano-particles ceramic was showed the highest density about 5.9 g/cm3, Vickers micro-hardness was 8.9 GPa, dielectric constant was 2005 and dielectric loss was 0.01 at 1 kHz frequency. [ABSTRACT FROM AUTHOR]

Lead-free Bi0.5(Na0.68K0.22Li0.10)0.5TiO3 + 0.003 mol Sm2O3 (BNKLT-Sm) ceramics were synthesized via the solid-state combustion technique with calcination temperatures between 750 and 850 °C and sintering temperatures between 1025 and 1100 °C for 2 h. The results showed that increasing the calcination temperature caused the percentage of perovskite phase and the particle size of the BNKLT-Sm powders increased. The BNKLT-Sm powder calcined at 800 °C displayed a pure perovskite structure without any impurity phases. The influence of the sintering temperature on the phase formation, microstructure and electrical properties of the ceramics was then investigated. All samples sintered at different temperatures possessed coexisting rhombohedral (R) and tetragonal (T) phases and the R phase became dominant when the sintering temperature increased. The microstructure of all ceramics showed a rectangular shape and anisotropic growth. The average grain size increased with increasing sintering temperature. Dielectric and ferroelectric behavior displayed relaxor characteristics in all samples. The maximum dielectric constant at Tm (εm) of 4777 and the highest remnant polarization (Pr) of 5.03 µC/cm2 were obtained by the densest ceramics (5.85 g/cm3), which was sintered at 1075 °C for 2 h. [ABSTRACT FROM AUTHOR]

Binary system ceramics of 0.92Bi0.5(Na0.68K0.22Li0.10)0.5TiO3-0.08Ba0.5Sr0.5TiO3 (abbreviation as 0.92BNKLT-0.08BST) were prepared by the solid-state combustion method. Different sintering temperatures (between 1050 and 1150 °C for 2 h) were investigated for their effects on the structural phase, microstructure and electrical properties. 0.92BNKLT-0.08BST ceramics showed a pure perovskite structure with coexisting phases of rhombohedral and tetragonal, in all samples. The tetragonality and the lattice parameters increased with increasing sintering temperatures. The ceramics' grains showed polygonal shapes with anisotropic growth. The average grain size increased from approximately 0.35 to 0.83 µm when the sintering temperature increased from 1050 to 1150 °C. The highest density of 5.83 g/cm3 and the maximum dielectric constant at Tm (εm) 5006 were obtained by the sample sintered at 1100 °C for 2 h. With higher sintering temperatures, the P-E hysteresis curves exhibited more pinched loops which indicated higher relaxor behavior. A large strain of 0.21% and a high normalized strain piezoelectric coefficient ( d 33 * ), around 420 pm/V, were achieved at the sintering temperature of 1125 °C for 2 h. [ABSTRACT FROM AUTHOR]

Lead-free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3-xNiO (x = 0, 0.2, 0.4, 0.6 and 0.8 wt%) ceramics were prepared by the solid-state combustion technique using glycine as a fuel. The effect of NiO doping on the phase formation, microstructure, electrical and magnetic properties of the ceramics was investigated. The powders and ceramics were calcined and sintered at a temperature of 1050 °C and 1450 °C for 2 h, respectively. XRD results showed that all ceramics had coexisting orthorhombic and tetragonal phases. Increasing the amount of NiO doping enhanced the amount of tetragonal phase, as verified by the Rietveld refinement technique. The density values (ρ) and the average grain size rapidly decreased from 5.79 to 4.69 g/cm3 and 37.8 ± 3.6 to 3.0 ± 0.3 µm when NiO doping increased from 0 to 0.8 wt%. The values of the dielectric constant (ε), dielectric loss (tan δ) and remnant polarization (Pr) tended to decrease when NiO doping increased. Only the sample with 0.4 wt% NiO exhibited ferromagnetic behavior at room temperature, with a remnant magnetization (Mr) and a coercive field (Hc) of 1.04 × 10−5 emu/g and 72.55 Oe, respectively. [ABSTRACT FROM AUTHOR]

Ba0.97Ca0.03Ti0.94Sn0.06O3 ceramics with Fe2O3 doping (BCTS-xFe; x = 0, 0.001, 0.002, 0.003, 0.004 and 0.005) were synthesized via the solid-state combustion technique. The influence of small amounts of Fe2O3 doping on the phase evolution, microstructure, electrical and magnetic properties of BCTS ceramics was investigated. We found that increasing Fe2O3 doped content changed the crystal structure from coexisting tetragonal and orthorhombic phases to a pseudo-cubic phase. The grain size, εc and Pr decreased rapidly with increasing Fe2O3 content. Moreover, TO-T and TC moved to lower temperatures and the maximum dielectric constant became significantly reduced with increased Fe2O3 doping. The BCTS ceramics with doped Fe2O3 displayed paramagnetic characteristics. [ABSTRACT FROM AUTHOR]

The effects of Cs+ substitution and direct doping in (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) ceramics, on the crystal structure, microstructure and electrical properties were investigated. Both the KNNT with Cs+ substitution (K0.5-xCsxNNT) and addition (KNNT-xCs) (x = 0, 0.01, 0.02, 0.03 and 0.04 mol%) were synthesized by the solid-state combustion technique using glycine as fuel. All samples were sintered at 1130–1150 °C for 4 h. The x-ray diffraction (XRD) analysis for the ceramics revealed the presence of orthorhombic (O) and tetragonal (T) phases in all samples. Increasing both the Cs+ substitution and doping amounts, enhanced the content of orthorhombic phase, as verified by the Rietveld refinement technique. It was found that Cs+ doping, either substitutional or additional, strongly decreased their density, dielectric and ferroelectric properties. The undoped KNNT ceramic exhibited well-saturated P-E hysteresis loop. With Cs+ doping, the samples became unsaturated and a leakage current was produced. The KNNT-xCs ceramics demonstrated higher density and dielectric properties than the K0.5-xCsxNNT ceramics. [ABSTRACT FROM AUTHOR]

The effect of NiO doping (0–0.8 wt%) on the phase structure, microstructure, dielectric and magnetic properties of 0.99(K0.45Na0.52Li0.03)(Nb0.94Sb0.06)O3-0.01BiScO3 (KNLNS-BS) ceramics was investigated. The samples were fabricated by the solid-state combustion technique with glycine used as fuel. Powders and ceramics were calcined and sintered at temperatures of 700 °C for 1 h and 1120 °C for 3 h, respectively. The phase formation from the XRD results showed a pure perovskite structure with coexisting rhombohedral and tetragonal phases in all samples. The ratio of the rhombohedral and tetragonal phases (R:T) of the 0.6 wt% NiO doped sample was 40:60, as verified by the Rietveld refinement technique. The grain morphology of the ceramics exhibited irregular polyhedron shapes and the average grain size was in the range of 1.3 ± 0.15 to 2.6 ± 0.51 µm. KNLNS-BS ceramics with 0.6 wt% added NiO had the highest density (4.40 g/cm3) and the highest maximum dielectric constant (εC= 5013). Without NiO doping, the ceramic showed diamagnetic behavior, whereas all of the NiO-doped ceramics exhibited paramagnetic behavior measured at a temperature of 50 K. [ABSTRACT FROM AUTHOR]

This article reports the effect of Cu2+ substitution on the phase formation, morphology and electrical behavior of Bi0.5Na0.34K0.11Li0.05Ti(1-x)CuxO3 with 0 ≤ x ≤ 0.020 (BNKLT-xCu) ceramics prepared by the solid state combustion technique with glycine used as the fuel. All samples were prepared with a calcination temperature and a sintering temperature of 750 °C and 1025 °C, respectively for 2 h. The XRD results of all compositions revealed a single perovskite structure and that Cu2+ diffused efficiently into B-sites of the lattice, producing a BNKLT-xCu solid solution. The phase formation of the BNKLT-xCu ceramics showed coexisting rhombohedral (R) and tetragonal (T) phases in all samples. The highest measured density of the BNKLT ceramics was 5.99 g/cm3 and good dielectric properties measured at the temperature of the maximum dielectric constant (εm = 4723 and tanδ = 0.054), were obtained by the sample with Cu2+ substituted at x = 0.010. The BNKLT-xCu ceramics with Cu2+ ≥ 0.005 showed pinched P-E loops, and the negative strain of the S-E loops started to disappear, owing to the Cu2+ induced transformation from the ferroelectric (FE) phase to the ergodic relaxor (ER) phase. With Cu2+ levels of 0.010, the d*33 value increased to 705 pm/V, indicating that this sample was near the FE–ER phase boundary with induced high strain. Substituting an appropriate amount of Cu2+ improved the densification of BNKLT-xCu ceramics as capillary forces in the liquid phase during sintering pulled the grains together, which increased the εm values. [ABSTRACT FROM AUTHOR]

The effect of the firing conditions on the phase formation, microstructure, and electrical properties of (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) ceramics synthesized by the solid-state combustion technique using glycine as fuel has been investigated. All samples were calcined at 600°C to 800°C for 2 h and sintered at 1150°C to 1190°C for 2 h to 5 h. Pure KNNT powders were produced after calcination at 600°C for 2 h. The average particle size increased when the calcination temperature was increased. The KNNT powder calcined at 600°C for 2 h showed rather square morphology with average particle size of ∼ 160 nm. The x-ray diffraction (XRD) analysis results for the ceramics revealed the presence of orthorhombic (O) and tetragonal (T) phases in all samples. When sintering at 1150°C for 4 h, the O:T ratio was 50:50, as verified by the Rietveld refinement technique. The average grain size, density values, and dielectric properties tended to increase when the dwell time was increased from 2 h to 4 h, but then degraded. The KNNT ceramic produced at the optimum firing condition (1150°C for 4 h) showed good crystalline morphology, the highest density (ρ = 5.28 g/cm3), the highest dielectric constant (εC = 5002), and good ferroelectric behavior (Pr = 18.50 μC/cm2 and Ec = 9.04 kV/cm). [ABSTRACT FROM AUTHOR]

Herein, the effect of Fe3+ ions substitution on the phase evolution, microstructure, electrical, and magnetic properties of Bi0.5(Na0.68K0.22Li0.10)0.5Ti1−xFexO3 (BNKLT‐xFe) ceramics with 0 ≤ x ≤ 0.020 is investigated. The BNKLT‐xFe ceramics are synthesized via the solid‐state combustion method. All BNKLT‐xFe compositions use a calcination temperature of 750 °C for 2 h and a sintering temperature of 1025 °C for 2 h. The X‐ray diffraction (XRD) and Raman spectra illustrate coexisting rhombohedral (R) and tetragonal (T) phases in all compositions and the R phase increases with increasing Fe content. The X‐ray absorption spectroscopy (XAS) technique confirms that the local R symmetry increases from 38.8% to 67.0% with increasing x content from 0 to 0.020. The average grain size gradually increases from 0.52 to 0.84 μm when the x content increases from 0 to 0.020. At x = 0.010, the ceramic has high ferroelectric properties (Pr ≈ 26.8 μC cm−2, Ec ≈ 20.4 kV cm−1) and the highest normalized strain (d33*) of 386 pm V−1. In addition, the maximum value of the temperature‐dependent dielectric constant of 6136 is found at x = 0.015. Although BNKLT‐0Fe ceramic show diamagnetic behavior, paramagnetic behavior is observed in all Fe3+ substituted samples. [ABSTRACT FROM AUTHOR]

In this work, Co0.6Zn0.4Fe1.6Cr0.4O4 nanoparticles were synthesized by the solid state combustion technique and calcined at various temperatures from 700 to 900 °C. The phase formation, morphology and local structure of the calcined samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray absorption near edge structure (XANES) techniques. The XRD analysis revealed existence of the single-phase cubic spinel structure in the samples calcined at 900 °C. The average crystallite sizes increased as the calcination temperature increased. The XANES spectra allowed the valence states of Co2+, Cr3+, Fe3+ and Zn2+ ions in all calcined samples to be established. The clear agreement between measured and ab initio theoretical XANES spectra was the strongest evidence of Cr3+ and Zn2+ ions substituting for Co2+ and Fe3+, respectively, in CoFe2O4 inverse spinel structure. XANES results also suggested that the site occupancy of Co2+, Cr3+, Fe3+ and Zn2+ ions was mixed, with the majority Co2+ and Cr3+ ions occupying octahedral sites and the majority of Fe3+ ions occupying tetrahedral sites, while the Zn2+ ions equally occupied octahedral and tetrahedral sites in a ratio of 50:50. [ABSTRACT FROM AUTHOR]

In this study, we mixed Bi0.5(Na0.68K0.22Li0.1)0.5TiO3 (with 0.10 wt.% of La2O3 added-abbreviate to BNKLLT) solid solution to (K0.44Na0.52 Li0.04)(Nb0.84Ta0.10Sb0.06)O3 (abbreviate to KNLNTS), forming a (1 − x) KNLNTS–xBNKLLT solid solution (0 ≤ x ≤ 0.030 wt.%) prepared via the solid state combustion technique. We examined the effect of the x content on the phase formation, morphology and electrical behavior of these ceramics. The x-ray diffraction of all samples showed a single perovskite phase, indicating that the BNKLLT solid solution effectively diffused into the KNLNTS lattice during the sintering process to form a solid solution. These ceramics showed coexisting orthorhombic and tetragonal phases. The tetragonality increased with an increase in x. An x concentration around 0.005–0.020 promoted a well-developed morphology and enhanced densification. With an x concentration > 0.020, the microstructure and density of the samples began to deteriorate. The phase transition temperature of the orthorhombic ferroelectric to the tetragonal ferroelectric phase disappeared while the Curie temperature of the (1 − x) KNLNTS–xBNKLLT samples reduced with x content ≥ 0.005. Moreover, the (1 − x) KNLNTS–xBNKLLT exhibited intermediate relaxor-like behaviors; i.e., between the normal and relaxor ferroelectric. The highest dielectric constant at room temperature (2126), the highest maximum dielectric constant (6625) and the maximum piezoeelctric coefficient (≅ 275 pC/N) were attained by the sample with an x content of 0.020 due to a morphotropic phase boundary at this concentration. Adding BNKLLT solid solution into KNLNTS resulted in the degeneration of the ferroelectric behavior in this ceramics system. Adding BNKLLT solid solution into KNLNTS ceramics at the right concentration is a new method for improving the physical behavior, dielectric and piezoelectric performance. [ABSTRACT FROM AUTHOR]

In this paper, we studied the effect of Cr2O3 doping (0–0.8 wt%) on the phase formation, dielectric, ferroelectric and magnetic properties of (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 (BCTZ) ceramics prepared by the solid state combustion method. All samples were prepared with a calcined and sintered temperature of 1050 °C and 1450 °C, respectively, for 2 h. The results of the XRD patterns showed the coexistence between the tetragonal (T) and orthorhombic (O) phases for all samples, and the tetragonal phase increased with increasing amounts of Cr2O3. The dielectric constant decreased when Cr2O3 increased. The P-E hysteresis loops of the BCTZ ceramics doped with Cr2O3 between 0 and 0.2 wt% showed slim and saturated loops. By increasing Cr2O3 doping from 0.4 to 0.8 wt%, the P-E loops were unsaturated and a leakage current was produced. The undoped BCTZ ceramics exhibited diamagnetic behavior. The sample with 0.2 wt% Cr2O3 showed ferromagnetic behavior. Increasing Cr2O3 doping from 0.4 to 0.8 wt%, caused the ceramics to exhibit paramagnetic behavior. Doping with Cr2O3 led to improper ratios between the tetragonal and orthorhombic phases, decreased density and increased porosity which caused a decrease in the electric properties. [ABSTRACT FROM AUTHOR]