Growth and characterization of Pb0.97La0.02(Zr0.66Sn0.27Ti0.07)O3 antiferroelectric single crystals

Single crystals of Pb_0.97La_0.02(Zr_0.66Sn_0.27Ti_0.07)O₃ (PLZST) with the composition near the morphotropic phase boundary were grown by the flux method. The PbO–PbF₂–B₂O₃ system was used as a solvent. PLZST single crystals with the size of 4–6 mm are obtained and these crystals are slightly translucent after polishing. The splitting of (200) reflection peak indicates that the obtained crystals are of a single phase with tetragonal perovskite structure. The element contents of the grown crystals were measured by inductively coupled plasma atomic emission spectrometry. The chemical composition of the crystals is Pb_0.979La_0.014(Zr_0.666Sn_0.285Ti_0.049)O₃. Thermal properties and dielectric properties of PLZST single crystals were studied. The results show that flux-grown PLZST single crystals exhibit obvious endothermic processes and relaxor behaviors near the phase transition temperatures.     

Structural and dielectric properties of Pb0.91(La,K)0.09(Zr0.65Ti0.35)0.9775O3 ceramics

Potassium-modified polycrystalline samples of PLZT, Pb_0.91(La_{1 – z/3}K_z)_0.09(Zr_0.65Ti_0.35)_0.9775O₃ [z = 0.0, 0.1, 0.3, 0.5, 0.7], were prepared using sol-gel technique. X-ray diffraction (XRD) of these compounds show that they can be formed in single phase at 800 °C. Pellets prepared from the above powders were sintered at 1100 °C. Detailed studies of the dielectric constant () and loss tangent (tan ) of the compounds at different frequencies (400 Hz to 10 kHz) at room temperature (RT) and temperature (RT to 350 °C) suggest that the compounds undergo ferroelectric phase transition of diffuse-type on increasing K-concentration. Analysis of diffuseness of these compounds gives a value close to 2, which indicates the presence of higher degree of disorder in PLZT substituted by K. The dielectric constant () is found to increase initially and then to decrease with increasing K concentration.     

Large electric field-induced strain near AFE/FE phase boundary in (Pb0.97La0.02)(Zr, Sn, Ti)O3 system

(Pb_0.97La_0.02)(Zr, Sn, Ti)O₃ ceramics were prepared by conventional solid state reaction process, and the effects of Zr⁴⁺/Sn⁴⁺ and Zr⁴⁺/Ti⁴⁺ ratios on the crystal structure, dielectric, ferroelectric, and electric field-induced strain properties were systemically investigated. The XRD results showed, with the increase of Zr⁴⁺ and Ti⁴⁺ contents, the stability of the specimens became weakened and a transformation from AFE to FE phase was observed at x = 0.65 and y = 0.12, respectively. In addition, it was observed that the strain first increased with a maximum value in the composition near AFE/FE phase boundary, and then decreased with increasing Zr⁴⁺ and Ti⁴⁺ contents. Further, with the decrease of measuring frequency, the strain continuously increased because the reversal of the domain can be more sufficient. The maximum strain of 0.55 % is obtained in Pb_0.97La_0.02(Zr_0.63Sn_0.26Ti_0.11)O₃ AFE ceramics at 1 Hz measuring frequency which lays a foundation for preparing actuators with high properties.     

Thickness-dependent dielectric and electrocaloric properties of Pb0.85La0.1(Zr0.85Ti0.15)O3 antiferroelectric thin films on stainless steel substrates

Journal of Materials Science: Materials in Electronics - Pb0.85La0.1(Zr0.85Ti0.15)O3 (PLZT) antiferroelectric (AFE) thin films with different thicknesses were prepared by the sol–gel method...     

Bipolar electric fatigue behaviour as a function of field strength in antiferroelectric (Pb,Ba,La)(Zr,Sn,Ti)O3 ceramics

The bipolar electric fatigue behaviour of antiferroelectric ceramics with the composition of Pb_0.88Ba_0.10La_0.02(Zr_0.55Sn_0.35Ti_0.10)O₃ was investigated under various cycling fields. The material exhibits a degradation in the maximum field induced strain, a diffuse AFE-FE phase transition and an enhancement in the diffusion character of the FE-AFE phase transition due to electric cycling. Those variations increase with cycle number, indicating a logarithmic fatigue up to 10⁸ cycles. There is no indication for the variations to be recovered, and the symmetry of the negative and positive parts of the strain hysteresis loops still remains. Higher cycling field results in a stronger deterioration of the maximum field induced strain and a larger extent of diffusion in AFE-FE and FE-AFE phase transitions. The normalized maximum strain shows nearly the same scale of degradation when the materials are cycled at various electric fields. After a heat treatment at 500°C for 1 h, the variations in the AFE-FE and FE-AFE phase transition due to cycling disappear, whereas the maximum strain resumes almost to its original value. Electrochemical variations are considered to contribute to the main fatigue mechanism for the material under investigation.     

低相变场细电滞回线(Pb,La)(Zr,Sn,Ti)O_3反铁电陶瓷的研究

对远离反铁电-铁电准同型相界的(Pb,La)(Zr,Sn,Ti)O3反铁电组分进行Ba2+掺杂,制备出了细电滞回线、低相变电场的反铁电陶瓷,反铁电-铁电相变电场仅为1.5kV/mm,电场回滞减小到0.2kV/mm,并且极化强度和应变量随电场增大几乎呈线性变化,可通过调节电场大小得到不同的应变量,有利于开辟这类材料新的应用领域。     

Microwave dielectric properties of Mg(Zr0.05Ti0.95)O3-SrTiO3 ceramics

The microwave dielectric properties of (1−x)Mg(Zr_0.05Ti_0.95)O₃-xSrTiO₃ ceramics prepared by conventional solid processing were investigated. With increasing x, the dielectric constant and the quality factor decreased, and the temperature coefficient of resonant frequency was tuned from negative to positive value. The effect of sintering temperature on microwave properties was also studied. After sintering at 1,390 °C for 4 h, the ceramics exhibited a near zero temperature coefficient of resonant frequency about 2.1 ppm/°C, an optimum dielectric constant of 20.9 and a high quality factor of 203000 (6.8 GHz), at the level of x = 0.05.     

Study of dielectric and piezoelectric properties of Pb(Ni,Nb)O3–Pb(Zr,Ti)O3 ceramics using mechanically activated powder

In this paper, we report a new method to prepare the polymer/inorganic nanoparticle composites using electron irradiation-induced polymerization. The mixture of nanoparticles and MMA solution were co-irradiated by 1.6 MeV electron beam to a dose of 10, 20 and 30 kGy at a dose-rate of 60 kGy/h in air at room temperature. The products after irradiation were extracted using a soxhlet extractor with boiling xylene and investigated by X-ray diffraction (XRD), Fourier transmission infrared (FTIR), X-ray photoelectron spectroscopy (XPS), optical absorption spectra (OAP) and photoluminescence (PL). The FTIR and XPS results show that there exist some unextractable PMMA in the nanocomposites after extraction, indicating a strong interaction between the PMMA and nanoparticles. PL results show that new luminescence peaks appear at 415 and 420 nm for the nanocomposites of anatase and γ-Al₂O₃.     

铅基(Pb,La)(Zr,Ti)O_3反铁电厚膜微驱动结构的特性测试

采用金属醇盐为前驱体的溶胶-凝胶工艺,实现了PLZT反铁电厚膜晶圆级的制备。基于铅锆反铁电材料的相变应变效应和快速响应特性,结合微纳兼容制造关键技术,研制出具有大应变、快响应、低驱动特性的硅基(Pb,La)(Zr,Ti)O3反铁电厚膜微悬臂梁构件。3种激励模式的测试结果表明,定频模式下梁的最大位移和速率相对于扫频模式下高出数倍,且定频模式(Square)更有利于激发反铁电材料相变,使得微悬臂梁驱动构件产生更大的应变和更快的响应速度,为大行程驱动位移和快速响应新型微执行构件的设计提供一种新的技术途径。     

Effects of cobalt and sintering temperature on electrical properties of Ba0.98Ca0.02Zr0.02Ti0.98O3 lead-free ceramics

Lead-free (Ba_0.98Ca_0.02)(Zr_0.02Ti_0.98)O₃-xmol% (x = 0–1.6) cobalt ceramics (BCZT-xCo) have been fabricated by the traditional solid-state reaction technique and the effects of Co and sintering temperature on ferroelectric, dielectric and piezoelectric properties of (Ba_0.98Ca_0.02)(Zr_0.02Ti_0.98)O₃ lead-free ceramics have been studied systematically. The orthorhombic–tetragonal (T _O–T) transition shift towards lower temperature with increasing Co addition, while Curie temperature (T _c) remained at relatively high value of 107 °C. And the Main piezoelectric parameters are optimized at x = 0.8 mol% with a high piezoelectric coefficient (d ₃₃ = 330 pC/N), a planar mode electromechanical coupling factor (k _p = 46.7 %), a high dielectric constant (ε _r = 2,675) and a low dielectric loss (tanδ = 0.90 %) at 1kHZ. Besides these, high remnant polarization (P _r) and low coercive field (E _c) of 11.5 μC/cm², 0.31 kV/cm are also obtained at (Ba_0.98Ca_0.02)(Zr_0.02Ti_0.98)O₃-0.8 mol%Co lead-free ceramics. Furthermore, greatly enhanced temperature stability of the piezoelectric properties was obtained in the temperature range from 20 to 90 °C. The above results indicate that BCZT-Co ceramics are promising lead-free materials for practical applications.     

Effect of Zr/Ti ratio on the dielectric and piezoelectric properties of Mn-doped Ba(Zr,Ti)O3 ceramics

Lead-free piezoelectric Ba(Zr _y Ti_1?y )O₃:0.5 mol%Mn (abbreviated as BZTM-100y, y = 0.04, 0.045, 0.05, and 0.055) ceramics were prepared via the conventional solid-state reaction method. The cubic to tetragonal phase transition temperature (T _c ) shifts to lower temperature with increasing Zr concentration, and the transition temperature from tetragonal to orthorhombic (T _o?t ) which is a shift to higher temperature from 26 to 47 °C with increasing y value from 0.04 to 0.055. And a small amount of Mn can improve effectively the electrical properties, especially the piezoelectric properties of the BZT ceramics. Compared to the pure BZT ceramics, the Mn-doped BZTM ceramic shows an excellent piezoelectric coefficient d ₃₃ as 213 pC/N.     

复合添加La_2O_3/MgO对(Zr_(0.8)Sn_(0.2))TiO_4陶瓷性能的影响

讨论了复合添加La2O3/MgO对(Zr0.8Sn0.2)TiO4介质陶瓷烧结机制和微波介电性能的影响。结果表明,La2O3/MgO对(Zr0.8Sn0.2)TiO4的烧结有一定的促进作用,但La2O3/MgO添加量的增大会造成晶格缺陷和残留气孔的增多,从而导致材料的密度和Q×f降低。在1320℃保温12h、La2O3/MgO添加量为0.9wt%时,(Zr0.8Sn0.2)TiO4介电性能最好,其εr=37.14,Q×f=36600,τf=7.77×10-6/℃。     

Measurement and modeling of dielectric properties of Pb(Zr,Ti)O3 ferroelectric thin films

In this study, the real and imaginary parts of the complex permittivity of lead zirconate titanate ferroelectric thin films are studied in the frequency range of 100 Hz to 100 MHz. The permittivity is well fitted by the Cole-Cole model. The variation of the relaxation time with the temperature is described by the Arrhenius law and an activation energy of 0.38 eV is found. Because of its nonlinear character, the dielectric response of the ferroelectric sample depends on the amplitude of the applied ac electric field. The permittivity is composed of three different contributions: the first is due to intrinsic lattice, the second is due to domain wall vibrations, and the third is due to domain wall jumps between pinning centers. This last contribution depends on the electric field, so it is important to control the field amplitude to obtain the desired values of permittivity and tunability.     

Effects of sintering method on the structural,dielectric and energy storage properties of AgNbO3 lead-free antiferroelectric ceramics

In this work, we systematically investigated the effects of single-step and two-step sintering methods on the structural, dielectric and energy storage properties of pure AgNbO₃ lead-free antiferroelectric ceramics. Compared with the single-step sintered ceramic, the ceramic prepared by two-step sintering method has smaller grain size, dense and homogeneous microstructure. In addition, the results of dielectric temperature spectra reveal that the two-step sintering method hardly changes the phase transition temperature of AgNbO₃ ceramics but greatly decreases the dielectric loss value. Most importantly, the ceramic prepared by the two-step sintering method displays high breakdown electric field strength (22 kV/mm), larger recoverable energy storage density-W_rec (2.59 J/cm³) and higher energy storage efficiency-η (45%) as well as excellent temperature stability than those of the ceramic by single-step sintering method. Furthermore, it also exhibited high power density (P_D?=?25.7 MW/cm³) and extremely fast charge–discharge speed (25 ns). Our results provide a simple and novel way to design high-performance AgNbO₃-based energy storage lead-free ceramics.

Graphical abstract