Characterization of Ba(Zr0.05 Ti0.95)O3 thin film prepared by sol-gel process

Ba(Zr_0.05Ti_0.95)O₃ (BZT) thin film (∼330 nm) was grown on Pt/Ti/SiO₂/Si(100) substrate by a simple sol-gel process. The microstructure and the surface morphology of BZT thin film were studied by X-ray diffraction and atomic force microscopy. The optical properties of BZT thin film were obtained by spectroscopic ellipsometry. The optical bandgap was found to be 3.74 eV of direct-transition type. Ferroelectric and dielectric properties of BZT thin film were also discussed. The electrical measurements were conducted on BZT films in metal-ferroelectric-metal (MFM) capacitor configuration. The results showed the film exhibited good ferroelectrity with remanent polarization and coercive electric field of 3.54 μC/cm² and 95.5 kV/cm, respectively. At 10 kHz, the dielectric constant and dielectric loss of the film are 201 and 0.029, respectively.     

Dielectric properties of (Ba1-2x Sr x Ca x )TiO3 ferroelectric ceramics

Ferroelectric ceramics of (Ba_1?2x Sr _x Ca _x )TiO₃ (0?≤?x?≤?0.30) were prepared by a routine solid-state reaction technique. Co-substitution of Sr²⁺ and Ca²⁺ for Ba²⁺ with equal mole in BaTiO₃ restrain the maximal dielectric constant K _m strongly when 0.2?≥?x?>?0. However, composition (Ba_0.4Sr_0.3Ca_0.3)TiO₃ shows the higher maximal dielectric constant. With increasing Sr and Ca content x, temperature T _m of the maximal dielectric constant K _m shifts to low temperature and all selected compositions for study exhibit a broad phase transition temperature range. The composition (Ba_0.4Sr_0.3Ca_0.3)TiO₃ presents characteristics of ferroelectric relaxor, value of K _m decreases and temperature T _m increases with increasing frequency.     

MSnO3(M=Ca,Sr,Ba)的溶胶-凝胶法合成及性能

采用溶胶-凝胶法制备了钙钛矿结构的MSnO3(M=Ca,Sr,Ba)晶体.将其作为锂离子电池负极材料的活性物质,利用恒电流电池测试仪研究其电化学性能.结果表明:CaSnO3、SrSnO3和BaSnO3的首次放电容量分别为894.3 mAh/g、703.8 mAh/g和673.6 mAh/g,首次充电容量分别为418.3 mAh/g、257.8 mAh/g和224.8 mAh/g,不可逆容量损失分别达53.2%、63.3%和66.6%.     

Dielectric and ferroelectric properties of Nb-doped Ba0.8Sr0.2TiO3 ceramics

Ferroelectric and dielectric properties were investigated for Ba_0.8Sr_0.2Ti_(1?5/4x)Nb _x O₃ ceramics with different Nb₂O₅ concentrations. The relations between the ceramic structures and those properties were discussed. The Ba_0.8Sr_0.2TiO₃ doping with 0.01mol% Nb₂O₅ appears to have a strong ferroelectric effect and better dielectric properties. The max permittivity (? _max) is up to 7,521.3 and Ba_0.8Sr_0.2Ti_(1?5/4x)Nb _x O₃ ceramics has higher permittivity even at room temperature. The permittivity presents broadened curves at large temperature ranges, which suggests a non Curie–Weiss behavior near the transition temperature. The diffuse phase transition coefficient (δ) for Ba_0.8Sr_0.2Ti_(1?5/4x)Nb _x O₃ doping with 0.01mol% Nb₂O₅ reaches 0.098, and its P–E loop expresses a diffusing curve. The remanent polarization (2P _r) and coercive field are 31.3 μC/cm² and 10 kV/cm, respectively. The P–E loop presents a diffusing curve, which is relative to the relaxor characteristic.     

水热法制备Ba(Ti0.9Sn0.1)O3纳米粉体

以二水合氯化钡、四氯化钛、五水合氯化锡为原料,于碱性环境240℃水热合成12 h得到了平均粒径为(80±10)nm、比表面积为10.8 m2/g的单分散Ba(Ti0.9Sn0.1)O3纳米粉体。与SEM、激光粒度测试仪和BET三种方法分析得到的粉末平均粒径相吻合,表明所得粉末呈单分散状态。研究了反应物初始浓度、矿化剂氢氧化钾过量浓度及反应温度对合成Ba(Ti0.9Sn0.1)O3粉体的影响。     

Dielectric and relaxor ferroelectric properties of Ba-doped Pb(Zr,Ti)O3 ceramics

(Pb,Ba)(Zr,Ti)O₃ is a relaxor ferroelectric material. Dielectric and ferroelectric properties of (Pb_1-x Ba _x )(Zr_0.70Ti_0.30)O₃ ceramics have been investigated for compositions varying in the range of 0.20?≤?x?≤?0.30. Reagent grade PbO, ZrO₂, TiO₂ and BaCO₃ raw powders were used, ceramics were fabricated by convenient solid state reaction. The experimental results show that the substitution of Ba for Pb can enhance the ferroelectric relaxor characteristics. With the Ba content increasing, the electric hysteresis was narrowed and the polarization was reduced. Meanwhile the temperature T _m that corresponding to the maximal dielectric constant was decreased. It has also been found that the hydrostatic pressure may cause the phase transition more diffuse and move T _m to higher temperature.     

Dielectric characteristics investigation of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 ferroelectric thin films

By the radio frequency (RF) magnetron sputtering methods, (Ba_0.7Sr_0.3)(Ti_0.9Zr_0.1)O₃ (BSTZ) ferroelectric thin films were deposited on the Pt/Ti/SiO₂/Si(100) substrates. The crystal structural and microstructure of these thin films were analyzed by means of the XRD, SEM, and AFM. Moreover, the dielectric characteristics were also investigated by the C-V and J-E analyses. The optimal deposition parameters for these BSTZ thin films were: RF power is 160 W, oxygen concentration is 25%, substrate temperature is 580°C, and chamber pressure is 0.075 mPa. Under these optimal deposition conditions, the (111) and (110) oriented polycrystalline of the BSTZ thin films grow easily. And under a bias voltage of 0.5 MV/cm, the dielectric constant and leakage current density of the BSTZ thin films are 191 and 3×10^?8 A/cm², respectively. In addition, under various measured temperatures (0 ～ 80°C) and frequencies (100 kHz ～ 1 MHz), all the dielectric constants remain almost unchanged. Compared to BSTZ thin films reported previously, in this study, the deposited thin films have the advantage of lower leakage current and hence are suitable for the applications of dynamic random access memory.     

Low-Temperature Process of Ferroelectric (Y0.95,Bi0.05)MnO3 Thin Films and Their Structural and Electrical Properties

[(Y_0.95,Bi_0.05)MnO₃] (YBM) films have been grown on Y₂O₃ buffered Si (001) by pulsed-laser deposition (PLD). We have compared the structural and dielectric properties of YBM films with those of typical YMnO₃ films from the viewpoint of lowering the process temperature. The highly c-axis oriented YBM film have been obtained on Y₂O₃/Si (001) at 700°C, which is a significantly reduced growth temperature from that of typical YMnO₃ films (850°C). The Bi modification was effective for the low temperature processing of YBM films. These highly c-axis oriented YBM films was obtained only at high ambient oxygen pressures, for example above 100 mTorr, contrary to YMnO₃ films which requires low ambient oxygen pressure for the growth of c-axis preferred orientation. The dielectric constant and dissipation factor was 29 and 0.017 at 1 MHz, respectively. The memory window due to ferroelectric polarization switching was found in a capacitance-voltage (C-V) characteristic. The YBM/Y₂O₃/Si structure with above characteristics of YBM films exhibited the C-V memory window of 1.2 V at a sweep voltage of 5 V. The flat-band voltage shifted symmetrically with increasing the sweep voltage up to 8 V due to little charge injection from Si. As a result, the memory window increased progressively with increasing the sweep voltage and amounted to 2 V at a sweep voltage of 8 V. The leakage current density was below 5 × 10^?7 A/cm² at a bias voltage of 8 V.     

Low temperature sintering of Ba0.91Ca0.09Ti0.916Sn0.084O3 lead-free piezoelectric ceramics with the additives of ZnO and MnO2

The objective of this work is to lower the sintering temperature of Ba_0.91Ca_0.09Ti_0.916Sn_0.084O₃ (BCTS) ceramics without sacrificing the piezoelectric performance. The low-temperature sintering technique has been conducted to prepare the BCTS ceramics by adding two additives of ZnO and MnO₂. The ceramics endure a phase transition from a ferroelectric tetragonal phase to a pseudo-cubic relaxor ferroelectric with increasing MnO₂ content. The addition of ZnO and MnO₂ decreases the sintering temperature greatly, positively affecting their dielectric and piezoelectric properties. An enhanced electrical behavior of d ₃₃?～?495 pC/N, k _p?～?43.0 %, ε _r?～?5429, and tan δ?～?1.54 % has been observed in the ceramic with x?=?0.1 wt% when sintered at ~1315 °C. As a result, the method to dope two additives of ZnO and MnO₂ can effectively improve the piezoelectric properties of BaTiO₃-based ceramics sintered at a low temperature.     

Dielectric and piezoelectric properties of La2O3 doped (Bi0.5Na0.5)0.92(Ba0.8Sr0.2)0.08 TiO3 lead-free piezoelectric ceramics

Lead-free piezoelectric ceramics (Bi_0.5Na_0.5)_0.92(Ba_0.8Sr_0.2)_0.08 TiO₃+x mol% La₂O₃(x = 0, 0.1, 0.3, 0.5, 0.8) were synthesized by conventional solid state reaction. The crystal structure of all compositions is mono-perovskite ascertained by XRD. The grain size decreased and diffuse phase transition behavior was more evident with the increasing amount of La₂O₃. The piezoelectric constant d₃₃ and the electromechanical coupling factor k_p showed the maximum value of 165 pC/N and 0.322 at 0.3% and 0.1% La₂O₃ addition, respectively, and rapidly decreased when La₂O₃ addition over 0.5%. The loss tangent tanδ linearly increased and the mechanical quality factor Q_m linearly decreased with the increasing amount of La₂O₃.     

Piezoelectric and ferroelectric properties of new Pb9Ce2Ti12O36 and lead-free Ba2NdTi2Nb3O15 ceramics

In this paper, measurements of the nonlinear ferroelectric, piezoelectric and dielectric properties of Pb₉Ce₂Ti₁₂O₃₆ (Pb₉CTO) and Ba₂NdTi₂Nb₃O₁₅ (BNTN) ferroelectric ceramics are presented. Hysteresis P(E) loops were measured as a function of applied electric field, frequency and temperature. The coercive field (E _c) and remnant polarization (P _r) displayed temperature and frequency dependence. Lead-free BNTN ceramics exhibited a coercive field E _c?>?2.4 kV mm^?1 and a piezoelectric coefficient d ₃₃?=?2 pC N^?1. The hysteresis loop was pinched above 110°C and a linear response was observed at 155°C, typical of a paraelectric material. Pb₉CTO was shown to be ferroelectric with coercive field E _c?=?1.2 kV mm^?1 and a d ₃₃?=?65 pC N^?1. The frequency dependences of the impedance of the Pb₉CTO discs were analyzed.     

Phase Formation,Dielectric, Ferroelectric and Magnetic Properties of Cr2O3 Doped (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 Ceramics

Abstract

In this paper, we studied the effect of Cr₂O₃ doping (0–0.8?wt%) on the phase formation, dielectric, ferroelectric and magnetic properties of (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)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.     

Synthesis and piezoelectric properties of [Bi1-z(Na1-x-y-zKxLiy)]0.5BazTiO3 lead-free piezoelectric ceramics

[Bi_1-z(Na_1-x-y-zK_xLi_y)]_0.5Ba_zTiO₃ lead-free piezoelectric ceramics were fabricated by ordinary ceramic technique and the piezoelectric and ferroelectric properties of the ceramics were studied. The ceramics can be well sintered at 1,100–1,150 °C for 2 h. X-ray diffraction (XRD) analysis shows that K⁺, Li⁺ and Ba²⁺ diffuse into the Bi_0.5Na_0.5TiO₃ lattices to form a solid solution with a single-phase perovskite structure. The introduction of K⁺, Li⁺ and Ba²⁺ into Bi_0.5Na_0.5TiO₃ significantly decreases the coercive field E _c but maintains the large remanent polarization P _r of the materials. The ceramics provide piezoelectric constant d ₃₃ of 205 pC/N, electromechanical coupling factor k _p of 0.346, remanent polarization P _r of 31.7–38.5 μC/cm², and coercive field E _c of 3.18–5.16 kV/mm.     

Effect of BiAlO3 concentration on the dielectric and piezoelectric properties of lead-free (Bi0.5Na0.5)0.94Ba0.06TiO3 piezoelectric ceramics

In this paper, lead-free (1-x)(Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃-xBiAlO₃ (BNBT-BA, x?=?0, 0.010, 0.015, 0.020, 0.025, and 0.030) piezoelectric ceramics were synthesized using a conventional solid-state reaction method. The effect of BiAlO₃ concentration on dielectric, ferroelectric and piezoelectric properties were investigated. The ferroelectric and piezoelectric properties of BNBT ceramics are significantly influenced by the presence of BA. In the composition range studied, X-ray diffraction revealed a perovskite phase with the coexistence of rhombohedral and tetragonal phases. The temperature dependence of dielectric properties showed that the depolarization temperature (T _d) shifted towards lower temperatures and that the degree of diffuseness of the phase transition around T _d and T _m became more obvious with increasing BiAlO₃ content. The remanent polarization increased with increasing BA, and reached a maximum value of 30 μC/cm² at x?=?0.020. As a result, at x?=?0.020, the piezoelectric constant (d ₃₃) and the electromechanical coupling factor (k _p) of the ceramics attained maximum values of 188 pC/N and 34.4 %, respectively. These results indicate that BNBT-BA ceramics is a promising candidate for lead-free piezoelectric materials.     

Structural and magnetic properties of Ba0.98Zn0.02Ti1-xMnxO3 ceramics

Our paper reports the influence of Mn doping on structural, magnetic and electrical properties of Ba_0.98Zn_0.02Ti_1-xMn_xO₃ ceramics (here x?=?0.04, 0.06, 0.08). Structural and magnetic properties are significantly modified by changing Mn ion concentration at Ti site. With the increase in Mn ion concentration (x?≥?0.04), structural phase transition occurs from tetragonal to hexagonal. Magnetization hysteresis loop is broaden and enhanced magnetization is observed with increase in Mn ion concentration. This enhanced magnetic effect is likely to originate from exchange interactions between different oxidation states of Mn ions. All compositions showed ferroelectric behavior. It clearly enumerates from our observations that magnetism especially ferromagnetism can be induced in the barium titanate ferroelectric ceramic with control of suitable substituents.     

Phase transition,electrical properties and large strain response in lead-free (1-x-y)BNT-xBKT-yKNN ceramics

Abstract

Lead-free piezoelectric composition ceramics of (1-x-y)Bi_0.5Na_0.5TiO₃–xBi_0.5K_0.5TiO₃–yK_0.5Na_0.5NbO₃; (1-x-y)BNT-xBKT-yKNN (with 0.18≤x?≤?0.26 and 0≤y?≤?0.07) were fabricated using the solid-state combustion method. The structure exhibited co-existing rhombohedral and tetragonal phases for all samples. Increasing of x and y contents, the average grain size decreased from 1.42?μm to 1.02?μm and 1.25?μm to 0.70?μm, respectively. The diffuseness exponent (γ) of the ceramics was between 1.817 and 1.939 for x composition and between 1.766 and 1.999 for y composition indicating that the (1-x-y)BNT-xBKT-yKNN solid solutions had diffuse phase transition behavior. The change in the P-E loops of the ceramics indicated that the long-range ferroelectric order of the samples was disturbed and turned to the polar nano-regions (PNRs) with increased x and y contents. The polarization hysteresis loop transformed from well saturated typical ferroelectric, to pinched, and then to the relaxor state with increased x and y content. The addition of BKT and KNN contents significantly enhances the field-induced strain in BNT ceramics. The largest S_max of 0.25% corresponded to a high-field effective d₃₃* of 509?pm/V, which was found in the composition of 0.79BNT-0.20BKT-0.01KNN.     

High piezoelectric properties of (Ba,Ca)TiO3-0.04LiF ceramics sintered at a low temperature

Lead-free piezoelectric ceramics are strongly needed to replace the lead-based piezoelectric ceramics with increasing environmental concerns. Barium titanate (BaTiO₃) systems are one of the most promising candidates due to excellent electrical properties. However, the sintering temperature for traditionally sintered BaTiO₃ ceramics are about 1300°C, which restricts the applications of BaTiO₃ ceramics. It is necessary to develop high piezoelectric properties of BaTiO₃ based ceramics which are able to sinter at low temperature. The (Ba_0.94Ca_x)Ti_0.94O_δ-0.04LiF (x?=?0.00?~?0.05 mol) ceramics were synthesized by a conventional sintering method at 1050°C. All the samples show high relative densities over 90%. X-Ray Diffraction pattern indicated that the crystallographic structure of the samples (x?=?0.00 and 0.01 mol) are orthorhombic phase and changes to pseudocubic one with increasing Ca content to x?=?0.03 mol. Two-phases with orthorhombic and pseudocubic symmetries coexisted at x?=?0.02 mol, which contributes the excellent properties, in which the piezoelectric constant d ₃₃?=?361 pC/N, the planar electromechanical coupling coefficient k_p?=?41.2%, the Curie temperature Tc?=?70°C, the temperature of phase transition T _O-PC?=?34°C near the room temperature, the relative permittivity ε _r?=?4028 and the remanent polarization P _r?=?9.39 μC/cm².     

Growth,Microwave Properties and Microstructure of Ba0.05Sr0.95TiO3 Thin Films

Charged defects were found to have a significant influence over the microwave properties of Ba_0.05Sr_0.95TiO₃ thin films.     

Substrate effect on in-plane ferroelectric and dielectric properties of Ba0.7Sr0.3TiO3 thin films

Heteroepitaxial Ba_0.7Sr_0.3TiO₃ thin films were grown on (LaAlO₃)_0.3(Sr₂AlTaO₆)_0.35 (001) (LSAT) and SrTiO₃ (001) (STO) single crystal substrates using pulsed laser deposition (PLD). X-ray diffraction characterization revealed a good crystallinity and a pure perovskite structure for films grown on both LSAT and STO substrates. The in-plane ferroelectric and dielectric properties of the films were studied using interdigital electrodes (IDE). The film grown on LSAT substrate exhibited an enhanced in-plane ferroelectricity, including a well-defined P-E hysteresis loop with the remnant polarization P _r = 10.5 μC/cm² and a butterfly-shaped C-V curve. Nevertheless, only a slim hysteresis loop was observed in the film grown on STO substrate. Curie temperature T _c of the film grown on LSAT substrate was found to be ∼105^∘C, which is nearly 70^∘C higher than that of the bulk Ba_0.7Sr_0.3TiO₃ ceramics. T _c of the film grown on STO substrate has almost no change compared to the bulk Ba_0.7Sr_0.3TiO₃ ceramics. The dielectric tunabilities were found to be 64% and 52% at 1 MHz for the films grown on LSAT and STO substrates, respectively.     

Structural and dielectric properties of BaCexTi1-xO3 ceramics

ABSTRACT

In this paper, we prepare silver nanowires circuit graphics by UV-curing technology. The optimal condition of preparation of the silver nanowires circuit graphics are examined. Experiment results show that the UV-curing technology is a kind of individual, low-cost and environment-friendly method to prepare silver nanowires circuit graphics. The main influence factors on the lines' width are the UV beam power and scanning speed. And we also study the influence of the hot pressing temperature on the resistivity of the circuit graphics. In the experiments, the optimal condition is that the UV beam power is 190 mW and the scanning rate is 6 cm/s, then we get the minimum line width, which is 0.25 mm. The thickness of silver nanowires layer is 100 µm and the hot pressing temperature is 100°C, we will get the sample whose resistivity is 21× 10^?5 Ω·cm.