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Bismuth layer structured ferroelectrics (BLSFs) have drawn much attention due to their great potential for high‐temperature applications. It is generally accepted that BLSFs with small orthorhombic distortion should have low TC. In this paper, we report an anomalous example Li0.5Bi2.5Nb2O9 (LBN), which has small orthorhombic distortion but very high TC. LBN shows the highest TC (834°C) among currently reported prototype alkali‐metal BLSFs, which is attributed to its small tolerance factor. However, the refinement result reveals that LBN is orthorhombic with the space group of A21am, and the orthorhombic distortion of LBN a/b is merely 1.0019. The measurement of piezoelectric coefficient (d33 ∼ 6 pC/N) and observation of striped domain structure confirm the ferroelectricity nature of LBN. This work deepens our understanding of BLSFs and may lead to the finding of more novel BLSFs with high performance. [ABSTRACT FROM AUTHOR]

The pressure‐driven explosive energy‐conversion (EEC) effect of ferroelectric (FE) materials has been extensively studied in scientific research and high‐tech applications owing to its high pulse‐power output capability. The fundamental principle of this effect is pressure‐driven phase transition and depolarization in FE materials, accompanied by discharging behavior from the charge release upon pressure loading. Pb(Zr,Ti)O3 has been an excellent example of a materials exhibiting these properties. However, recent investigations have been focused on developing other lead‐based or lead‐free materials with a higher energy‐storage ability and better temperature stability. In this article, we review the recent progress achieved in the past decades on different types of lead‐based and lead‐free ceramics, single crystals, and multilayer films, based on their unique pressure‐driven phase transition and energy‐conversion properties. Their pulse power discharging performance under actual shock‐wave compression is also summarized, followed by a detailed discussion of the failure mechanism under shock‐wave compression. Finally, several issues and perspectives are proposed for future investigation in this area. All these not only assist in the design of new materials for high‐performance EEC but are also helpful for the practical application of these promising materials in pulse‐power technologies. [ABSTRACT FROM AUTHOR]

Utilizing temperature and magnetic field dependent dielectric spectroscopy, two different dielectric relaxation processes, both accompanied with prominent positive magnetodielectric (MD) effects, were observed in Pt/BiScO3-PbTiO3/La0.7Sr0.3MnO3 (Pt/BSPT/LSMO) heterostructure. An equivalent circuit model is established to quantitatively describe the relaxation data well. The simulation results elucidated that one relaxation process can be attributed to magnetic order associated BSPT/LSMO interfacial relaxation with abnormal dynamics feature. Another one is due to the external contact interface contributions. Both relaxation dynamics can be tuned, via magnetic field controlled localization of free interfacial charges, to induce MD effects in BSPT/LSMO interfaces and nonmagnetic Pt/BSPT contacts. [ABSTRACT FROM AUTHOR]

We report the electric-field-induced ferroelectric (FEIN) to antiferroelectric (AFE) phase transition that is tuned by the poling temperatures in 0.89Bi0.5Na0.5TiO3-0.06BaTiO3-0.05K0.5Na0.5NbO3 (0.89BNT-0.06BT-0.05KNN) ceramics. Phase transition and pyroelectric behaviors of the ceramics were investigated as functions of temperature and electric field. Pyroelectric coefficient peaks of (3 ∼ 6.5) × 10-8 C cm-2 K-1 are detected at about 10 °C above the poling temperatures for the samples poled at different temperatures. The poling temperature tuned pyroelectric behaviors are attributed to the FEIN to AFE phase transition when the temperature increases. [ABSTRACT FROM AUTHOR]

A magnetoelectric (ME) heterostructure was fabricated by depositing a Ni‐Mn‐Ga (NMG) magnetic film on an antiferroelectric (AFE) PLZST—(Pb, La)(Zr, Sn, Ti)O3—ceramic substrate. Significant and reversible electric field‐induced relative magnetization changes (∆M/M0) were firstly observed in this magnetic/AFE heterostructure, and the ∆M/M0 vs electric field loops have been found to correspond well with the strain‐electric field curve of PLZST ceramic. The maximum ∆M/M0 variation can reach 15%, indicating an obvious strain‐mediated converse magnetoelectric (CME) effect. A maximum CME coefficient of 1.14 × 10‐9 s/m was obtained at the switching electric fields of PLZST. The collected results suggest that AFE materials with a large electric‐field‐induced phase transition strain could be alternative candidates in ME coupling heterostructures. [ABSTRACT FROM AUTHOR]

The ferroelectric hysteresis loops of 63PbTiO3-37BiScO3 ceramics were measured under sinusoidal electric fields in the range of frequency from 0.1 to 100 Hz and field from 5 to 55 kV/cm. The fitting results showed two linear relations existed between the logarithm of hysteresis area and the logarithm of the amplitude of field E0 in the first and third field region. In the second region, no linear relation existed due to polarization reversal. These three-stage behaviors were distinct from the existing two-stage behaviors. The slopes in the third stage increase with the increasing of frequency, which can be attributed to dielectric loss under high frequency. [ABSTRACT FROM AUTHOR]

The temperature scaling relations of the dynamic hysteresis were investigated in Zr-rich lead zirconate titanate (PZT) bulk ceramics. At each relation curve, there is a discontinuous district corresponding to the low- and high-temperature phase transitions. The temperatures are divided into low-T region and high-T region. At each temperature region, three power-law scaling relations were obtained for hysteresis area , coercivity Ec, and remnant polarization Pr with T, respectively. The six temperature scaling relations are field dependent and the simplified forms are different from the results obtained from the soft and hard PZT ceramics. [ABSTRACT FROM AUTHOR]

The depolarization temperature Td determines the upper temperature limit for the application of piezoelectric materials. However, the origin of depolarization behavior for Bi-based materials still remains controversial and the mechanism is intricate for different (Bi0.5Na0.5)TiO3-based systems. In this work, the structure and depolarization behavior of (1-x)(Bi0.5Na0.5)TiO3-xBiAlO3 (BNT-BA, x = 0, 0.02, 0.04, 0.06, 0.07) ceramics were investigated using a combination of X-ray diffraction and electrical measurements. It was found that as temperature increased, the induced long-range ferroelectric phase irreversibly transformed to the relaxor phase as evidenced by the temperature-dependent ferroelectric and dielectric properties, which corresponded to a gradual structural change from the rhombohedral to the pseudocubic phase. Therefore, the thermal depolarization behavior of BNT-BA ceramics was proposed to be directly related to the rhombohedral–pseudocubic transition. Furthermore, Td (obtained from thermally stimulated depolarization currents curves) was higher than the induced ferroelectric-relaxor phase transition temperature TFR (measured from dielectric curves). The phenomenon was quite different from other reported BNT-based systems, which may suggest the formation of polar nanoregions (PNRs) within macrodomains prior to the detexturation of short-range ferroelectric domains with PNRs or nanodomains. [ABSTRACT FROM AUTHOR]

Highly (001) oriented ( K, Na) NbO3 ( KNN) lead-free piezoelectric thin films were grown on LaNiO3 ( LNO)-coated silicon by RF magnetron sputtering. The effects of the top electrodes on the electrical properties of KNN thin films were investigated. The dielectric and piezoelectric properties were remarkably improved in LNO/ KNN/ LNO (εr = 899 at 1 kHz, d33 = 58 pm/V), compared with that in Pt/ KNN/ LNO (εr = 584 at 1 kHz, d33 = 26 pm/V). An enhanced ferroelectricity was also obtained in LNO/ KNN/ LNO, with a remnant polarization of 12 μC/cm2 and a maximum polarization of 23 μC/cm2 at the applied field of 200 kV/cm. Besides, the temperature dependence of piezoelectricity of the films was characterized in this study. [ABSTRACT FROM AUTHOR]

Energy-storage properties of 0.89 Bi0.5Na0.5TiO3-0.06 BaTiO3-0.05 K0.5Na0.5NbO3 (0.89 BNT-0.06 BT-0.05 KNN) lead-free ceramics were first investigated. Measurements of dielectric properties together with switching current curves indicate a rather diffuse ferroelectric ( FE) to anti-ferroelectric ( AFE) phase transition when heating from 20°C to 90°C. The energy density ( W), which was calculated from P-E hysteresis loops, increases linearly with the external electric field when E exceeds AFE- FE transition field. W is independent of temperature and frequency, and maintains around 0.59 J/cm3 under 5.6 kV/mm in the stable AFE phase region. These properties indicate that 0.89 BNT-0.06 BT-0.05 KNN ceramics might be a promising lead-free AFE material for energy-storage capacitor application. [ABSTRACT FROM AUTHOR]

Antiferroelectric Pb(Zr, Nb, Ti)O3 (PZNT) films were deposited via a sol-gel process on Pt(111)/Ti/SiO2/Si, LaNiO3- and La0.5Sr0.5CoO3-buffered Si substrate. The scaling behavior of the energy density W of antiferroelectric films was investigated. The scaling behavior of W against frequency f of PZNT on LaNiO3-buffered Si takes the form of W ∝ f0.08, which differs significantly from that form of W ∝ f-0.14 of PZNT on La0.5Sr0.5CoO3-buffered Si. This indicates that the scaling relations of W vary substantially as bottom electrodes change and might be closely related to the variation of nonuniform strain field and depolarization field within the AFE films. [ABSTRACT FROM AUTHOR]

It is the behavior of electric-field induced antiferroelectric to ferroelectric (AFE-FE) phase transition that determines the specific application scenario of antiferroelectric materials. Here, we report that the evolution of the atomic displacement ordering from full-ordered to semi-ordered modulation should be responsible for the change in the behavior of the AFE-FE transition from sharp to diffuse. The novel semi-ordered configuration is originated from the competing interaction between long-range displacement modulation and compositional inhomogeneity, which just makes the AFE-FE transition diffuse but maintains the switching field. These results provide atomic-scale understanding for AFE-FE transition and new insights for designing hysteresis-free antiferroelectric materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Currently, there is an urgent need of extraordinary comprehensive pyroelectric materials for the wide application in detectors and energy harvesters. In this study, the (Pb 1–1.5 x La x)(Zr 0.86 Ti 0.14)O 3 (abbreviated as PLZT, x = 0.02, 0.03, 0.04 and 0.05) ceramics located in ferroelectric-antiferroelectric (FE-AFE) phase boundary were designed and synthesized by using conventional solid-state reaction method. The microstructures, phase structures, dielectric, ferroelectric, thermal depolarization and pyroelectric properties of the PLZT ceramics with different La content were investigated thoroughly. The XRD results show that the PLZT ceramics change from FE phase to AFE phase with increasing La content. The significant improvement of pyroelectric coefficient p and figures of merit (FOMs) are achieved in the PLZT ceramics with the increase in La content because of the increased metastable ferroelectric phase under the application of electric field. The (Pb 0.955 La 0.03)(Zr 0.86 Ti 0.14)O 3 (x = 0.03) ceramic exhibits not only high p of 5.2 × 10 − 8 C / cm 2 K and high depolarization temperature (T d) of 179 ℃ but also excellent FOMs with F i = 2.2 × 10 − 10 m / V , F v = 5.0 × 10 − 2 m 2 / C , and F d = 3.47 × 10 − 5 Pa − 1 / 2 . In addition, the highest p of 6.8 × 10 − 8 C / cm 2 K is achieved in (Pb 0.94 La 0.04)(Zr 0.86 Ti 0.14)O 3 (x = 0.04) ceramic. These results demonstrate that the PLZT ceramics of x = 0.03 and 0.04 are promising candidates for pyroelectric applications. [ABSTRACT FROM AUTHOR]

Highly (001)-oriented pure PbZrO 3 (PZO) films and Sn-substituted PZO films are deposited on (001)-LaNiO 3 buffered SiO 2 /Si substrates by RF magnetron sputtering. Different Sn-substituted PbZrO 3 films (PbZr 1-x Sn x O 3 , x = 0%, 3%, 5%, 10%) with orthorhombic anti-ferroelectric phase are fabricated. The effects of Sn substitution on structure and energy performance have been investigated in detail. The switching electric fields are enlarged and energy loss is lowered by Sn substitution. Recoverable energy density (Wr) of 14.8 ± 0.2 J/cm 3 and energy efficiency (η) of 71.2 ± 0.5% at 900 kV/cm are obtained in 5% Sn-substituted PZO film (~ 360 nm). Furthermore, with thicker thickness of ~ 650 nm, Wr and η can be further improved. The Sn-substituted PZO film is believed to be an improved material for applications in energy storage systems and 5% Sn-substituted PZO film exhibits the highest Wr and η in this work. [ABSTRACT FROM AUTHOR]

Abstract: Pb0.4Sr0.6TiO3/LaNiO3 (PST/LNO) thin film with a perfect (100) orientation was deposited on SiO2/Si substrate by magnetron sputtering method. Both Pt and LNO top electrodes have been prepared on this film to investigate the electrical properties. The dielectric constant and piezoelectric coefficient significantly increase while the average coercive field is strongly lowered when LNO is used as the top electrode. A large tunability of 77% (@300kV/cm) and low loss factor of 2.85% were obtained. Also, a maximum and remnant piezoelectric coefficients (d 33max.eff. and d 33rem.eff.) values of 90pm/V and 47pm/V were observed. These measured properties indicate that the PST thin film is a multi-functional material, which is a promising candidate for piezoelectric applications and for tunability devices. [Copyright &y& Elsevier]

Abstract: Ferroelectricity in Langmuir–Blodgett (LB) films (Z-type and alternated Y-type) of nitrogencrown (NC) and arachidic acid (AA) was investigated by electric polarization measurements and small angle X-ray diffraction (SAXD). For Z-type AA LB multilayer and the AA LB films incorporating barium ions, as well as for Z-type NC LB multilayer and the Y-type NC/AA alternating LB films, hysteresis loops of the samples were observed and confirmed existence of the remnant polarizations in the LB films. Their corresponding remnant polarizations were found to be 15, 180, 450 and 9400μCm−2, respectively. Therefore, the maximum ratios of remnant polarizations up to 620 (9400/15)-folds were obtained from NC/AA alternating LB films. The enhancement of ferroelectricity in NC/AA alternating LB films was observed for the first time. It was demonstrated that the enhancement of ferroelectricity in the LB films could be created by incorporation of barium ions into the LB film structures and strong interaction due to electron clouds redistribution largely originated from the compact insertion configuration of AA between two chains of NC molecules in interleaving films. [Copyright &y& Elsevier]

Abstract: Polarization–field (P–E) hysteresis loops of – bulk ceramics were measured under sinusoidal electric fields over a frequency range of Hz and an amplitude range of 20–50 kV/cm. The scaling relations of the hysteresis loop area versus the frequency and amplitude of the applied field for the saturated loops take different forms in the low and high frequency ranges. From these two relations, it can be concluded that the relationship is a power law increase in the low frequency range while in the high frequency range the relationship turns into a power law decrease. [Copyright &y& Elsevier]