Dielectric Properties of Ba0.8Ca0.2TiO3–Bi(Mg0.5,Ti0.5)O3–NaNbO3 Ceramics

Ceramics in the system 0.45Ba_0.8Ca_0.2TiO₃–(0.55?x)Bi(Mg_0.5Ti_0.5)O₃–xNaNbO₃, x = 0–0.02 were fabricated by a conventional solid‐state reaction route. X‐ray powder diffraction indicated cubic or pseudocubic symmetry for all samples. The parent 0.45Ba_0.8Ca_0.2TiO₃–0.55Bi(Mg_0.5Ti_0.5)O₃ composition is a relaxor dielectric with a near‐stable temperature coefficient of relative permittivity, ε_r = 950 ± 10% across the temperature range 80°C–600°C. Incorporation of NaNbO₃ at x = 0.2 extends the lower working temperature to ≤25°C, with ε_r = 575% ± 15% from temperatures ≤25°C to >400°C, and tan δ < 0.025 from 25°C to 400°C. Values of dc resistivity ranged from ~10⁹ Ω·m at 250°C to ~10⁶ Ω·m at 500°C. The properties suggest that this material may be of interest for high‐temperature capacitor applications.     

Dielectric stability in the relaxor: Na0.5Bi0.5TiO3-Ba0.8Ca0.2TiO3-Bi(Mg0.5Ti0.5)O3- NaNbO3 ceramic system

Ceramics with temperature-stable dielectric characteristics have been developed in the system: 0.6[0.85Na_0.5Bi_0.5TiO₃-(0.15-x)Ba_0.8Ca_0.2TiO₃-xBi(Mg_0.5Ti_0.5)O₃]?0.4NaNbO₃, x ≤ 0.15. Dielectric measurements exhibited relaxor ferroelectric characteristics with temperature-stable relative permittivity from ε_r~1330 ± 15% in the temperature range from ?70?°C to 215?°C and tanδ ≤ 0.02 from ?20?°C to 380?°C for x = 0 compositions. For the Bi(Mg_0.5Ti_0.5)O₃ modified compositions the temperature range of stable relative permittivity extended from ?70?°C to 400?°C, with ε_r ~ 950 ± 15% and tanδ ≤ 0.02 from ?70?°C to 260?°C. Values of dc resistivity were ~ 10⁸ Ω?m at a temperature of 300?°C and the corresponding RC constant values were in the range from 0.40 ? 0.78?s at 300?°C. All ceramic samples exhibited a linear polarisation-electric field response at maximum applied electric field of 5?kV/cm (1?kHz).     

Stability of High‐Temperature Dielectric Properties for (1 − x)Ba0.8Ca0.2TiO3–xBi(Mg0.5Ti0.5)O3 Ceramics

Ceramics in the solid solution system, (1 ? x)Ba_0.8Ca_0.2TiO₃–xBi(Mg_0.5Ti_0.5)O₃, were prepared by a conventional mixed oxide route. Single‐phase perovskite‐type X‐ray diffraction patterns were observed for compositions x < 0.6. A change from tetragonal to single‐phase cubic X‐ray patterns occurred at x ≥ 0.1. Dielectric measurements indicated relaxor behavior for x ≥ 0.1. Increasing the Bi(Mg_0.5Ti_0.5)O₃ content improved the temperature sensitivity of relative permittivity ?_r at high temperatures. At x = 0.5, a near‐plateau relative permittivity, 835 ± 40, extended across the temperature range, 65°C–550°C; the permittivity increased at x = 0.6 to 2170 ± 100 for temperatures 160°C–400°C (1 kHz). The corresponding loss tangent, tanδ, was ≤0.025 for temperatures between 100°C and 430°C for composition x = 0.5; at x = 0.6, losses increased sharply at >300°C. Comparisons of dielectric properties with other materials proposed for high‐temperature capacitor applications suggest that (1 ? x)Ba_0.8Ca_0.2TiO₃–xBi(Mg_0.5Ti_0.5)O₃ ceramics are a promising base material for further development.     

High quality factor microwave dielectric ceramics in the (Mg1/3Nb2/3)O2–ZrO2–TiO2 ternary system

Novel high quality factor microwave dielectric ceramics (1?x)ZrTiO₄?x(Mg_1/3Nb_2/3)TiO₄ (0.325≤x≤0.4) and (ZrTi)_1?y(Mg_1/3Nb_2/3)_yO₄ (0.2≤y≤0.5) with the addition of 0.5 wt% MnCO₃ in the (Mg_1/3Nb_2/3)O₂–ZrO₂–TiO₂ ternary system were prepared, using solid‐state reaction method. The relationship between the structure and microwave dielectric properties of the ceramics was studied. The XRD patterns of the sintered samples reveal the main phase belonged to α‐PbO₂‐type structure. Raman spectroscopy and infrared reflectivity (IR) spectra were employed to evaluate phonon modes of ceramics. The 0.65ZrTiO₄?0.35(Mg_1/3Nb_2/3)TiO₄?0.5 wt% MnCO₃ ceramic can be well densified at 1240°C for 2 hours and exhibits good microwave dielectric properties with a relative permittivity (ε_r) of 42.5, a quality factor (Q×f) value of 43 520 GHz (at 5.9 Ghz) and temperature coefficient of resonant frequency (τ_f) value of ?5ppm/°C. Furthermore, the (ZrTi)_0.7(Mg_1/3Nb_2/3)_0.3O₄?0.5 wt% MnCO₃ ceramic sintered at 1260°C for 2 hours possesses a ε_r of 31.8, a Q×f value of 35 640 GHz (at 6.3 GHz) and a near zero τ_f value of ?5.9 ppm/°C. The results demonstrated that the (Mg_1/3Nb_2/3)O₂–ZrO₂–TiO₂ ternary system with excellent properties was a promising material for microwave electronic device applications.     

Ferroelectric to Relaxor Transition in BaTiO3–Bi(Zn2/3Nb1/3)O3 Ceramics

The (1?x)BaTiO₃–xBi(Zn_2/3Nb_1/3)O₃ (x = 0.01–0.30) ceramics were synthesized by solid‐state reactions. The solubility limit was determined to be x = 0.20. A systematic structural transition from a tetragonal phase (x ≤ 0.034), to a mixture of tetragonal and rhombohedral phases (0.038 ≤ x ≤ 0.20), and finally to a pseudocubic phase (x ≥ 0.22) at room temperature was identified. Dielectric measurement revealed a ferroelectric (x ≤ 0.04) to relaxor (x ≥ 0.06) transition with permittivity peak broadening and flattening, which was further verified by Raman spectroscopy and differential scanning calorimetry (DSC). Activation energies obtained from the Vogel–Fulcher model displayed an increasing trend from ~0.03 eV for x ~ 0.05, to unusually high values (>0.20 eV) for the compositions with x ≥ 0.15. With the increase in Bi(Zn_2/3Nb_1/3)O₃ content, the polarization hysteresis demonstrated a tendency from high nonlinearity to sublinearity coupled with the reduction in remnant polarization and coervice field. The deconvolution of the irreversible/reversible polarization contribution was enabled by first‐order reversal curve distributions, which indicates that the decreasing polarization nonlinearity with the increase in Bi(Zn_2/3Nb_1/3)O₃ concentration could be related with the change from the ferroelectric domain and domain wall contributions to the weakly coupled relaxor behaviors.     

Effects of Postdensification Annealing upon Microstructures and Microwave Dielectric Characteristics in Ba((Co0.6−x/2Zn0.4−x/2Mgx)1/3Nb2/3)O3 Ceramics

Effects of postdensification annealing upon microstructures and microwave dielectric characteristics in Ba((Co_0.6?x/2Zn_0.4?x/2Mg_x)_1/3Nb_2/3)O₃ (x = 0, 0.1, 0.2, and 0.3) complex perovskite ceramics have been investigated. Long‐time annealing at temperatures below the order–disorder transition temperature enhances the cation ordering degree and promotes the ordering domain growth. The most significant improvement of Qf value is obtained together with the suppressed temperature coefficient of resonant frequency in the samples annealed at 1400°C for 12 h, while the dielectric constant decreases slightly. The Qf value of ceramics annealed at 1400°C mainly attributes to the enhanced cation ordering degree, because their low‐energy domain boundaries are not detrimental to the Qf value. As the annealing temperature increases close to the transition temperature, coarse ordering domains with high‐energy boundaries are formed, and then the Qf value steadily decreases because of the inferior domain structure, even the cation ordering degree increases. The microwave dielectric characteristics of Ba((Co_0.6?x/2Zn_0.4?x/2Mg_x)_1/3Nb_2/3)O₃ ceramics are affected by the common function of ordering degree and domain structure. The best combination of microwave dielectric characteristics is obtained in the composition of x = 0.3 after annealing at 1400°C for 12 h: ε_r = 33.2, Qf = 117 200 GHz, and τ_f = 8.6 ppm/°C.     

Crystal structure,defect relaxation,and microwave dielectric properties of Ba[(Mg1/3Nb2/3)1−xHfx]O3 solid solutions

Ba[(Mg_1/3Nb_2/3)_1?xHf_x]O₃ (BMNH, x = 0.05, 0.1, 0.15, 0.2) solid solutions were prepared via the solid‐state reaction method. The effect of BaHfO₃ on the crystal structure, microwave dielectric performance, and defect relaxation behavior of Ba(Mg_1/3Nb_2/3)O₃ (BMN) were studied. BaHfO₃ additions degraded the sintering activity of BMN powder, requiring a high sintering temperature (T_s) ~ 1650°C; but it could be effectively improved by a prolonged sintering process at a lower T_s of 1600°C. The well‐sintered BMNH ceramics (1600°C for 30 h) possessed a high densification >96%, and exhibited cubic perovskite structures without 1:2 cation ordering. Once doped with Hf, the low‐temperature relaxation in dielectric spectroscopy and thermally stimulated depolarization current (TSDC) for pure BMN disappeared, further indicating such relaxation is related to cation‐ordered structure. Oxygen vacancies, namely showing in‐grain and across‐grain‐boundary relaxation of ‐related defects, were the main defect types in BMNH. The concentrations of in‐grain decreased as x increased, which is beneficial to BMNH to maintain high Q × f values of 69 400‐73 000 GHz. Accompanied by a high ε_r of 33.27‐33.59 and a low τ_f of +13.6 to +20.7 ppm/°C, these materials have a good potential for applications in microwave components and devices.     

Formation of BaFe12−xNbxO19 and its high electromagnetic wave absorption properties in millimeter wave frequency range

BaFe_12?xNb_xO₁₉ (BFNO, x=0‐0.6) powders with Nb⁵⁺ substituting for Fe³⁺ were prepared by sol‐gel method. The formation process and electromagnetic (EM) wave absorption properties of the BFNO are investigated in detail. With Nb⁵⁺ content increasing from x=0 to x=0.6, the formation temperature of barium ferrite phase without heat time increases from ~700°C to ~900°C, while the appearance temperature of typical plate grains decreases from ~1300°C to ~1100°C, and the crystallization ability decreases at 600°C‐900°C, while the grain size increases gradually at 1100°C‐1300°C. Increasing sintering temperature and time promote the formation of barium ferrite phase and grain growth in all the samples. The ε′ and ε″ of the sample with x=0.6 sintered at 1300°C for 3 hours reach highest of ~7.9 and ~0.95 over 26.5‐40 GHz. Multiresonance peaks in permeability decrease from 40+ GHz to ~30 GHz with x rising from 0 to 0.6. Ultimately, small RL_min of ~?42 dB, thin d_m of ~0.76 mm, and broad bandwidth of >12 GHz can be exhibited simultaneously around millimeter wave atmospheric window of 35 GHz.     

High permittivity (1−x)Bi1/2Na1/2TiO3‐xPbMg1/3Nb2/3O3 ceramics for high‐temperature‐stable capacitors

(1?x)Bi_1/2Na_1/2TiO₃‐xPbMg_1/3Nb_2/3O₃[(1?x)BNT‐xPMN] ceramics have been fabricated via a conventional solid‐state method for compositions x ≤ 0.3. The microstructure, phase structure, ferroelectric, and dielectric properties of ceramics were systematically studied as high‐temperature capacitor materials. XRD pattern certified perovskite phase with no secondary phase in all compositions. As PMN concentration increased, the phase of (1?x)BNT‐xPMN ceramics transformed from ferroelectric to relaxor gradually at room temperature, with prominent enhancement of dielectric temperature stability. For the composition x = 0.2, the temperature coefficient of capacitance (TCC) was <15% in a wide temperature range from 56 to 350°C with high relative permittivity (>3300) and low dielectric loss (<0.02) at 150°C, which indicated promising future for (1?x)BNT‐xPMN system as high‐temperature stable capacitor materials.     

Novel BiFeO3–BaTiO3–Ba(Mg1/3Nb2/3)O3 Lead‐Free Relaxor Ferroelectric Ceramics for Energy‐Storage Capacitors

A novel lead‐free relaxor ferroelectric ceramic of (0.67?x)BiFeO₃–0.33BaTiO₃–xBa(Mg_1/3Nb_2/3)O₃ [(0.67?x)BF–0.33BT–xBMN, x = 0–0.1] was prepared by a solid‐state reaction method. A relatively high maximum polarization P_max of 38 μC/cm² and a low remanent polarization P_r of 5.7 μC/cm² were attained under 12.5 kV/mm in the x = 0.06 sample, leading to an excellent energy‐storage density of W ~1.56 J/cm³ and a moderate energy‐storage efficiency of η ~75%. Moreover, a good temperature stability of the energy storage was obtained in the x = 0.06 sample from 25°C to 190°C. The achievement of these characteristics was basically attributed to an electric field induced reversible ergodic to ferroelectric phase transition owing to similar free energies near a critical freezing temperature. The results indicate that the (0.67?x)BF–0.33BT–xBMN lead‐free realxor ferroelectric ceramic could be a promising dielectric material for energy‐storage capacitors.     

Temperature‐Stable Relative Permittivity from −70°C to 500°C in (Ba0.8Ca0.2)TiO3–Bi(Mg0.5Ti0.5)O3–NaNbO3 Ceramics

Temperature‐stable relaxor dielectrics have been developed in the solid solution system: 0.45Ba_0.8Ca_0.2TiO₃–(0.55 ? x)Bi(Mg_0.5Ti_0.5)O₃–xNaNbO₃. Ceramics of composition x = 0 have a relative permittivity ?_r = 950 ± 15% over a wide temperature range from +70°C to 600°C. Modification with NaNbO₃ at x = 0.2 decreases the lower limiting temperature to ?70°C, but also decreases relative permittivity such that ?_r ~ 600 ± 15% over the temperature range ?70°C to 500°C. For composition x = 0.3, the low‐temperature dispersion in loss tangent, tan δ, (at 1 kHz) shifts to lower temperature, giving tan δ values ≤0.02 across the temperature range ?60°C to 300°C in combination with ?_r ~ 550 ± 15%. Values of dc resistivity for all samples are of the order of 10¹⁰ Ω m at 250°C and 10⁷ Ω m at 400°C.     

Structural and Dielectric Properties in (1−x)BaTiO3–xBi(Mg1/2Ti1/2)O3 Ceramics (0.1 ≤ x ≤ 0.5) and Potential for High‐Voltage Multilayer Capacitors

Structural and dielectric properties of (1?x)BaTiO₃–xBi(Mg_1/2Ti_1/2)O₃ (x = 0.1–0.5) were investigated to understand the binary system and utilize it for high‐voltage, high energy density capacitors. The solubility limit for Bi(Mg_1/2Ti_1/2)O₃ in a BaTiO₃ perovskite was between x = 0.4 and x = 0.5. A phase with pseudocubic symmetry was formed for x = 0.1–0.4; a secondary phase developed at x = 0.5. Dielectric measurements showed highly diffusive and dispersive relaxor‐like characteristics from 10 to 40 mol% of Bi(Mg_1/2Ti_1/2)O₃. These compositions also showed high relative permittivity with low‐temperature coefficients of permittivity over a wide range of temperatures ?100°C–600°C. Relaxation behavior was quantitatively investigated using the Vogel–Fulcher model, which revealed the activation energy of 0.17–0.22 eV. Prototyped multilayer capacitors of 18 mm × 17 mm × 4 mm dimensions with a capacitance of 12.5 nF at 1 kHz were successfully constructed and demonstrated multiple charge–discharge characteristics up to 10 kV.     

Thermally Stable BaTiO3‐Bi(Mg2/3Nb1/3)O3 Solid Solution with High Relative Permittivity in a Broad Temperature Usage Range

A combined X‐ray diffraction (XRD), Raman spectra, X‐ray photoelectron spectroscopy, Scanning electron microscopy, and dielectric characterization of (1–x)BaTiO₃?xBi(Mg_2/3Nb_1/3)O₃ ceramic system were investigated for compositions of 0 ≤ x ≤ 0.2. Single‐phase perovskite‐type XRD patterns were observed for all compositions. A systematically structural change from tetragonal to pseudocubic symmetry occurred at 0.04 < x < 0.06, which agrees well with the analysis of Raman spectra. Dielectric measurements indicated that the crossover from a classic ferroelectric to relaxor ferroelectric occurred at x ≥ 0.04. Compared with other compositions, the temperature independence of relative permittivity at T > T_m significantly ameliorated at x = 0.1: near‐stable temperature coefficient of higher relative permittivity (~6800 ± 15%) and the corresponding loss tanδ ≤ 0.09 over a more broader temperature range of 25°C–240°C (1 kHz), which indicates that this ceramic is a promising dielectric material for elevated temperature dielectrics.     

Bi(Zn2/3Nb1/3)O3–(K0.5Na0.5)NbO3 High‐Temperature Lead‐FreeFerroelectric Ceramics with Low Capacitance Variation in a Broad Temperature Usage Range

The xBi(Zn_2/3Nb_1/3)O₃–(1?x)(K_0.5Na_0.5)NbO₃ (abbreviated as xBZN–(1?x)KNN) ceramics have been synthesized using the conventional solid‐state sintering method. The phase structure, dielectric properties and “relaxorlike” behavior of the ceramics were investigated. The 0.03BZN–0.97KNN ceramics show a broad and stable permittivity maximum near 2000 and lower dielectric loss (≤5%) at a broad temperature usage range (100°C–400°C) and the capacitance variation (ΔC/C_150°C) is maintained smaller than ±15%. The 0.03BZN–0.97KNN ceramics only possess the diffuse phase transition and no frequency dispersion of dielectric permittivity, which indicates that 0.03BZN–0.97KNN ceramics is a high temperature “relaxorlike” ferroelectric ceramics. These results indicate that 0.03BZN–0.97KNN ceramics are excellent promising candidates for preparing high‐temperature multilayer ceramics capacitors.     

Structural and Electrical Characteristics of (1−x)Pb(Lu1/2Nb1/2)O3–xPbTiO3 Ceramics with Low PbTiO3

A solid solution of (1?x)Pb(Lu_1/2Nb_1/2)O₃–xPbTiO₃ with composition of 0.01 ≤ x ≤ 0.08 have been prepared successfully. XRD analysis indicates the crystal structure adopts an orthorhombic (O) phase in 0.01 ≤ x ≤ 0.06 interval and becomes the coexistence of O and rhombohedral (R) phase at x = 0.07, then turns into R phase mostly at x = 0.08. In addition, two sets of superlattice reflections due to B‐site ordering and antiparallel cation displacement are distinguished by XRD and the superstructures which arise from antiparallel cation displacement disappear gradually with the increasing x. The grain size increases gradually with the increasing x, and then becomes the bimodal microstructure at x ≥ 0.06 due to the coexistence of O and R phase. The dielectric spectra exhibit Curie temperature decreases from 248°C to 147°C with increasing x from 0.01 to 0.08. As 0.01 ≤ x ≤ 0.04, the samples display typical double hysteresis loops, suggesting antiferroelectric nature, then turn into ferroelectric gradually at x = 0.05. Finally, it exhibit typical ferroelectric hysteresis loops in 0.06 ≤ x ≤ 0.08 interval.     

Effects of Mg Substitution on Order/disorder Transition,Microstructure, and Microwave Dielectric Characteristics of Ba((Co0.6Zn0.4)1/3Nb2/3)O3 Complex Perovskite Ceramics

Effects of Mg substitution on order/disorder transition, microstructure, and microwave dielectric characteristics of Ba((Co_0.6Zn_0.4)_1/3Nb_2/3)O₃ complex perovskite ceramics have been investigated. The ordered complex perovskite solid solutions are obtained in Ba((Co_0.6?x/2Zn_0.4?x/2Mg_x)_1/3Nb_2/3)O₃ ceramics (x = 0, 0.1, 0.2, and 0.3), and the ordering degree in the as‐sintered dense ceramics increases with increasing Mg‐substitution amount. The significantly improved Qf value is obtained in the present ceramics with increasing x, whereas the dielectric constant decreases slightly together with some increase of temperature coefficient of resonant frequency. The best combination of microwave dielectric characteristics is obtained in the composition of x = 0.3: ε_r = 33.7, Qf = 93 800 GHz, and τ_f = 9.6 ppm/°C. In the Mg‐substituted compositions, clear domain boundaries are obtained and the domain size increases as x increases, the highest Qf value is obtained when the domain size is about 40–60 nm in the ceramics with x = 0.3. The increased ordering degree and the fine ordering domain structure are considered to primarily contribute to the significant increase of Qf value in the Mg‐substituted Ba((Co_0.6Zn_0.4)_1/3Nb_2/3)O₃ complex perovskite ceramics.     

Large recoverable energy storage density and low sintering temperature in potassium‐sodium niobate‐based ceramics for multilayer pulsed power capacitors

Multilayer pulsed power ceramic capacitors require that dielectric ceramics possess not only large recoverable energy storage density (W_rec) but also low sintering temperature (<950°C) for using the inexpensive metals as the electrodes. However, lead‐free bulk ceramics usually show low W_rec (<2 J/cm³) and high sintering temperature (>1150°C), limiting their applications in multilayer pulsed power ceramic capacitors. In this work, large W_rec (~4.02 J/cm³ at 400 kV/cm) and low sintering temperature (940°C) are simultaneously achieved in 0.9(K_0.5Na_0.5)NbO₃–0.1Bi(Mg_2/3Nb_1/3)O₃–1.0 mol% CuO ceramics prepared using transition liquid phase sintering. W_rec of 4.02 J/cm³ is 2‐3 times as large as the reported value of other (Bi_0.5Na_0.5)TiO₃ and BaTiO₃‐based lead‐free bulk ceramics. The results reveal that 0.9(K_0.5Na_0.5)NbO₃–0.1Bi(Mg_2/3Nb_1/3)O₃–1.0 mol% CuO ceramics are promising candidates for fabricating multilayer pulsed power ceramic capacitors.     

Orthorhombic‐pseudocubic phase transition and piezoelectric properties of (Na0.5K0.5)(Nb1−xSbx)‐SrZrO3 ceramics

0.96(Na_0.5K_0.5)(Nb_1?xSb_x)‐0.04SrZrO₃ ceramics with 0.0≤x≤0.06 were well sintered at 1060°C for 6 hours without a secondary phase. Orthorhombic‐tetragonal transition temperature (T_O‐T) and Curie temperature (T_C) decreased with the addition of Sb₂O₅. The decrease in T_C was considerable compared to that in T_O‐T, and thus the tetragonal phase zone disappeared when x exceeded 0.03. Therefore, a broad peak for orthorhombic‐pseudocubic transition as opposed to that for orthorhombic‐tetragonal transition appeared at 115°C‐78.2°C for specimens with 0.04≤x≤0.06. An orthorhombic structure was observed for specimens with x≤0.03. However, the polymorphic phase boundary structure containing orthorhombic and pseudocubic structures was formed for the specimens 0.04≤x≤0.06. Furthermore, a specimen with x=0.055 exhibited a large piezoelectric strain constant of 325 pC/N, indicating that the coexistence of orthorhombic and pseudocubic structures could improve the piezoelectric properties of (Na_0.5K_0.5)NbO₃‐based lead‐free piezoelectric ceramics.     

Relaxor Ferroelectric BaTiO3–Bi(Mg2/3Nb1/3)O3 Ceramics for Energy Storage Application

Perovskite solid solution ceramics of (1 ? x)BaTiO₃–xBi(Mg_2/3Nb_1/3)O₃ (BT–BMN) (x = 0.05–0.2) were synthesized by solid‐state reaction technique. The results show that the BMN addition could lower the sintering temperature of BT‐based ceramics. X‐ray diffraction results reveal a pure perovskite structure for all studied samples. Dielectric measurements exhibit a relaxor‐like characteristic for the BT–BMN ceramics, where broadened phase transition peaks change to a temperature‐stable permittivity plateau (from ?50°C to 300°C) with increasing the BMN content (x = 0.2), and slim polarization–electric field hysteresis loops were observed in samples with x ≥ 0.1. The dielectric breakdown strength and electrical resistivity of BT–BMN ceramics show their maxima of 287.7 kV/cm and 1.53 × 10¹³ Ω cm at x = 0.15, and an energy density of about 1.13 J/cm³ is achieved in the sample of x = 0.1.     

Anisotropic domain structures of Pb(Mg1/3Nb2/3)O3–PbZrO3–PbTiO3 single crystals with high ferroelectric phase transition temperature

The anisotropic domain structures and local piezoresponse of rhombohedral Pb(Mg_1/3Nb_2/3)O₃–PbZrO₃–PbTiO₃ single crystals with high ferroelectric phase transition temperature (T_FE‐FE≥120°C) were systematically investigated by vector piezoresponse force microscopy. The typical size of labyrinthine domain pattern for [001]_C sample was in the range of 100‐200 nm, revealing its relaxor feature. While the [011]_C sample exhibited ordered ribbon‐shaped domain pattern with preferential alignment along <011> direction since the modulation effect of polar nanoregions. For [111]_C sample, it had messy and featureless domain patterns. For as‐grown crystal, the incorporation of Zr⁴⁺ cation in Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ system resulted in that the long‐range coulomb interactions of the charged ions in the short range order regions were weakened, leading to an increased relaxor feature. Concurrently, the incorporation of Zr⁴⁺ cation enhanced the Pb‐B repulsion intensity, resulting in an improved T_FE‐FE. Temperature‐dependent properties of as‐grown crystal exhibited good temperature stability from 30 to 120°C, indicating it is a promising material for actuator and ultrasonic transducer applications.