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BiFeO3–BaTiO3 (BF–BT) ceramics with high Curie temperature and excellent piezoelectric coefficient are expected to be applied in high-temperature piezoelectric sensors and actuators. However, its resistivity decreases rapidly with temperature and impedes its further applications. Moreover, normal methods such as doping modification cannot address this issue. In the present work, bismuth layered Bi4Ti2.93(Zn1/3Nb2/3)0.07O12 (BIT) and perovskite 0.36BiScO3-0.64PbTiO3 (BSPT) ceramics were selected as insulating layers and were, respectively, sintered with 0.7BF–0.3BT ceramics to form laminated ceramics. The heterojunction structures effectively prevent carrier migration, and both resistivities of BIT and BSPT laminated ceramics were increased from 106 to 108−9 Ω cm at 300 °C. In addition, piezoelectric properties of the BSPT-type laminated ceramics are much higher than that of BF–BT ceramics, in which the bipolar strain was increased from 0.04% to 0.1% (4 kV/mm), and d33 was increased from 140 to 237 pC/N. Therefore, designing the insulating layer may be an effective method to realize the high-temperature application for BF–BT ceramics. [ABSTRACT FROM AUTHOR]

This article was originally published online on 29 February 2024 with incorrect figures. All figures have been corrected. All online versions of this article were corrected on 17 July 2024. AIP Publishing apologizes for the errors.By Wenshuo Kang; Kai Zou; Zhiyong Zhou and Ruihong LiangReported by Author; Author; Author; Author [Extracted from the article]

Designing BiScO3‐PbTiO3 (BS–PT) ceramics that merge high Curie temperature (TC) and large piezoelectric coefficient (d33) has always been a significant challenge for high‐temperature applications. Doping is a commonly used and effective method for enhancing the electrical performances of piezoelectric ceramics. In this study, the Li+/W6+ acceptor–donor co‐doping method was used to enhance the piezoelectric properties of 0.36BiSc1‐xLixO3–0.64PbTi1‐yWyO3 (0.36x = 0.64y) ceramics. The optimal electrical performance was observed at x = 0.01 near morphotropic phase boundaries, with a large d33 (505 pC/N), high TC (407°C), huge remnant polarization (Pr ∼ 40.9 μC/cm2), and inverse piezoelectric coefficient (d33* = 601 pm/V). Rietveld refinement and piezoelectric force microscopy results revealed that incorporating Li+/W6+ into the BS–PT ceramics decreased the T phase proportion and domain size and increased the domain wall density. The enhancement in piezoelectricity can be attributed to the lowered energy barrier resulting from the reduced T‐phase proportion and complex domain structure, which promotes polarization rotation and facilitates domain wall motion. This work demonstrates that acceptor–donor co‐doping is a promising strategy for optimizing the electrical performance of the BS–PT ceramics. [ABSTRACT FROM AUTHOR]

Even though BiFeO3–BaTiO3 (BF–BT) with high Curie temperature and excellent piezoelectric properties is very suitable for high‐temperature applications, its rapid reduction in resistivity with temperature limits its further application. So far, there is no effective method to improve the resistivity of BF–BT at a high‐temperature state. In this work, hot‐press sintering combined with an oxygen atmosphere was used to prepare (1 − x)BF–xBT (x = 0.2–0.33) ceramics for the first time, which reduced the sintering temperature from 1000 to 920°C. The controllable grain size can be achieved by adjusting the sintering temperature and the applied pressure. The X‐ray photoelectron spectroscopy results confirmed that using hot‐press sintering effectively avoided the generation of heterovalent Fe ions, and the resistivity of BF–BT ceramics at the high‐temperature stage was improved by two orders of magnitude. It was found that hot‐press sintering can cause the oriented growth of the sample along the (1 1 0) direction, and further refined X‐ray diffraction was used to accurately analyze the changes in the lattice structure. The hot‐press sintered samples obtained larger polarization strength, especially the electro‐induced strain showed excellent temperature stability in the wide temperature range of 30–170°C. Hot‐pressing sintering combined with an oxygen atmosphere is more suitable for preparing high insulation and electrical breakdown resistance ceramics. [ABSTRACT FROM AUTHOR]

The composite design strategy for ferro‐piezoelectric ceramics has been successfully used to get excellent performances, whereas few studies focus on the electrochemical characteristics of the second phase in the composite. In this work, MgO, due to its high resistance insulation and high breakdown strength, was selected to be compounded with 0.7BiFeO3–0.3BaTiO3 (BFBT) ceramics. Intriguingly, an unreported second phase was derived from the solid‐state reaction and identifying its chemical composition as about Mg13Ti3Fe24O55. AC impedance technique was applied to clarify the electrical contribution of the second phase in composites. The results show that it has higher resistivity at the high‐temperature stage and more stable capacitance with temperature. Moreover, the second phase can improve the overall dielectric‐temperature stability. Ultimately, it indicates composite strategy can bring some beneficial effects on BFBT ceramics, and this present work may provide an alternative route for separating the electrical contribution of different regions for composite ceramics. [ABSTRACT FROM AUTHOR]

In the Internet age, information security is threatened anytime and anywhere and the copyright protection of audio and video as well as the need for matching detection is increasingly strong. In view of this need, this paper proposes a zero-watermarking algorithm for audio and video matching based on NSCT. The algorithm uses NSCT, DCT, SVD, and Schur decomposition to extract video features and audio features and generates zero-watermark stream through synthesis, which is stored in a third-party organization for detection and identification. The detection algorithm can obtain zero watermark from the audio and video to be tested and judge and locate tampering by comparing with the zero watermark of the third party. From the experimental results, this algorithm can not only detect whether the audio and video are mismatched due to tampering attacks but also locate the mismatched audio and video segments and protect the copyright. [ABSTRACT FROM AUTHOR]

Video watermarking is an important means of video and multimedia copyright protection, but the current watermarking algorithm is difficult to ensure high robustness under various attacks. In this paper, a video watermarking algorithm based on NSCT, pseudo 3D-DCT and NMF has been proposed. Combined with NSCT, 3D-DCT and NMF, the algorithm embeds the encrypted QR code copyright watermark into the NMF base matrix to improve the anti-attack ability of the watermark under the condition of invisibility. The experimental results show that the algorithm ensures the invisibility of the watermark with a high signal-to-noise ratio of the video, and meanwhile has high ability and robustness against common single and combined attacks, such as filtering, noise, compression, shear, rotation and so on. The issue that the video watermarking algorithm has poor resistance to various attacks, especially the shearing attack, has been solved in this paper; thus, it can be used for digital multimedia video copyright protection. [ABSTRACT FROM AUTHOR]

BaZr0.1Ti0.89Fe0.01O3(BZTF)was prepared by sol–gel method using Ba(CH3COO)2, ZrO(NO3)2 and [CH3(CH2)3O]4Ti as crude materials, La2O3 and Fe2O3 as doping materials, changing the amount of dopant and using different sintering temperatures. The influence of La doping on the crystal structure, micro structure and diffuse ferroelectric phase transition of the sample were investigated. XRD results showed that all samples showed a characteristic peak of a single perovskite type. The appropriate doping amount of La3+ can improve the electrical performance of the sample. With the increase in La content, the degree of lattice distortion of the sample increases, causing the Curie temperature to move toward the low temperature. At the same time, the increase in the degree of dispersion of ferroelectric phase transitions can be attributed to the growth of grains and the reduction of long-range ordered domains. When doped with 0.6 mol% La, the sample has the highest degree of dispersivity ferroelectric phase transition, and the dielectric properties is the best:(ε25℃ = 5680, tanδ = 0.044, Tc = 42℃, γ = 1.89). [ABSTRACT FROM AUTHOR]

The dielectric, piezoelectric properties and dispersive ferroelectric phase transitions of (0.84 − x) BaTiO3–0.16CaTiO3–xBaZrO3 ternary ceramics were investigated in this manuscript. The study found that the optimum BaZrO3 doping amount was 0.1 mol%. Compared to the binary system, the ternary system has a denser microstructure and a more uniform grain size, and more excellent electrical properties. The influence mechanism of BaZrO3 doping on the system was explained in detail by lattice theory and domain theory. [ABSTRACT FROM AUTHOR]

The effects of sintering temperature and doping amount of gadolinium ions on the microstructures and electrical properties of sol gel derived Ba (Zr0.1Ti0.9) O3 + xGd ceramics were investigated in this manuscript. XRD analysis showed that the main crystalline phase of BZT-xGd ceramic samples exhibit a perovskite structure without significantly change. The sample sintered at 1350 °C and doped with gadolinium ions of 0.5 mol% has uniform grain size and compact morphology. And the sample(1350 °C—0.5 mol%) also has a high piezoelectric charge coefficient of 131.33 pC/N, large plane electromechanical coupling coefficient of 0.22, high dielectric constant of 10504, and small dielectric loss of 0.01. The correlation of dielectric and piezoelectric properties of BZT-xGd ceramics with doping amount of Gd3+ ion has been explained by the lattice theory. [ABSTRACT FROM AUTHOR]