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As a momentum‐independent spin configuration, persistent spin texture (PST) could avoid spin relaxation and play an advantageous role in spin lifetime. Nevertheless, manipulation of PST is a challenge due to the limited materials and ambiguous structure–property relationships. Herein, we present electrically switchable PST in a new 2D perovskite ferroelectric, (PA)2CsPb2Br7 (where PA is n‐pentylammonium), which has a high Curie temperature of 349 K, evident spontaneous polarization (3.2 μC cm−2) and a low coercive electric field of 5.3 kV cm−1. The combination of symmetry‐breaking in ferroelectrics and effective spin‐orbit field facilitates intrinsic PST in the bulk and monolayer structure models. Strikingly, the directions of spin texture are reversible by switching the spontaneous electric polarization. This electric switching behavior relates to the tilting of PbBr6 octahedra and the reorientation of organic PA+ cations. Our studies on ferroelectric PST of 2D hybrid perovskites afford a platform for electrical spin texture manipulation. [ABSTRACT FROM AUTHOR]

The orthorhombic O and O′ structure phases of ABO3-type perovskites possess the same symmetry and quite different physical properties. In this work, a pressure induced isostructural O′–O phase transition with volume expansion and less distortion in DyFeO3 orthoferrite was experimentally observed and studied by high-pressure x-ray diffraction and Raman spectroscopy measurements. Up to 35.2 GPa, DyFeO3 crystallizes in an orthorhombic Pbnm symmetry structure. With no change in the symmetry group, distinct O′-phase and O-phase were verified below 13.1 GPa and above 15.1 GPa, respectively. Meanwhile, the lattice becomes less distorted and metrically pseudo-cubic on the high-pressure side. The cell volume expands by a step in the intermediate pressure window accompanied by a decrease in spontaneous strain. It is suggested that FeO6 octahedra are more compressible than DyO12 sites under pressure. This work claimed the physical mechanism underlying phonon dynamics and variation of local structure symmetry of DyFeO3, which can be considered as the basic view for RFeO3 perovskites. [ABSTRACT FROM AUTHOR]

The (001) plate-like BaTiO3 piezoelectric micromaterials are synthesized by topochemical microcrystal conversion technique. BaTiO3 plates with a length of 2~10 μm and thickness of 0.5~1.3 μm are obtained. The dependence of morphology on synthesis conditions is discussed in detail. The crystal symmetry and multiscale domain structures of BaTiO3 plates are systematically investigated by various characterizations. X-ray diffraction (XRD) and Raman spectra analyses demonstrate the tetragonal symmetry of the (001) oriented BaTiO3 plates at room temperature. The domain configurations of the micron BaTiO3 are investigated with a polarized light microscope (PLM) and piezoresponse force microscopy (PFM). The single-crystal-like quality and uniformity are supported by PLM observations. More importantly, the classical 90° banded ferroelectric domains of ~125 nm width are observed for the first time in such BaTiO3 plates. The domain features in the mesoscale BaTiO3 plate are discussed and compared with its bulk counterparts. The results may provide insights into understanding and designing the mesoscale BaTiO3 functional materials. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (PNCs) are endowed with extraordinary photophysical properties such as wide absorption spectra, high quantum yield, and narrow emission bands. However, the inherent shortcomings, especially the instability in polar solvents and water incompatibility, have hindered their application as probes in chem/bio sensing. In this review, we give a fundamental understanding of the challenges when using PNCs for chem/bio sensing and summarize recent progress in this area, including the application of PNCs in various sensors and the corresponding strategies to maintain their structural integrity. Finally, we provide perspectives to promote the future development of PNCs for chem/bio sensing applications. [ABSTRACT FROM AUTHOR]

Halide perovskites have received an immense attention in the field of optoelectronics due to their outstanding photophysical properties. But so far, lead‐based halide perovskites still account for most of the research, which raises concerns due to lead toxicity. Herein, a new design strategy is proposed utilizing a super large, energetically higher singlet and triplet energy levels aromatic organic cation to incorporate into the perovskite structure, forming ultra‐stable high‐performance 2D/3D (quasi‐2D) perovskite. The judicious molecular design of connecting all the phenyl groups at their meta sites ensures the simultaneous achievement of a large molecular weight and high singlet and triplet energy levels. The resulting quasi‐2D perovskite thin films not only exhibits excellent emission properties but also, surprisingly, show long‐term waterproof‐level stability. The robustness of these perovskites is confirmed by their extraordinary emission stability upon direct water immersion and almost undetectable lead release in water. Proof‐of‐concept of a water‐resistant color conversion‐type perovskite near‐infrared (NIR) light‐emitting diode (LED) is demonstrated, showing high external quantum efficiency (EQE) and power conversion efficiency (PCE) of 20.5% and 13.3%, respectively. It is believed these results and strategy pave a new way for realizing environmentally friendly lead halide materials and devices. [ABSTRACT FROM AUTHOR]

Using the data-mining machine learning technique and the non-equilibrium Green's function method in combination with density functional theory, we studied the electronic transport properties of the organic-inorganic hybrid perovskite MAPbI3. The band structures of MAPbI3 from first-principles show that the ferroelectric and antiferroelectric dipole configurations have very little influence on the energy bandgap. Furthermore, we investigated the tunnel junctions made of MAPbI3 and 48 different metal electrodes, with the same fixed lattice constant as MAPbI3. With the increase in the number of perovskite unit cells, the electron transmission coefficients are found to decrease exponentially in general. For data mining studies, several different methods are employed to develop models for predicting electron transport properties. In particular, the gradient boosting regression tree model was tested and found to be the most effective tool among all these algorithms for fast prediction of the electron transmission coefficients and performance ranking of all studied metal electrodes. [ABSTRACT FROM AUTHOR]

Abstract: Film thermocouples as the most effective tool are used to monitor the real‐time and accurate in situ temperature in harsh environment, which will demand their electrodes with high thermal‐resistant properties, high sensitivity, and stability. In this work, a series of solid solutions based on strontium lanthanum chromate were systematically investigated as new electrodes. LaCrO3 and La0.8Sr0.2CrO3 with some glass additives were chosen to fabricate high‐performance thick‐film thermocouple due to a bigger Fermi level difference between them. The thermocouple shows a high sensitivity (107.8 μV/°C) during static calibration, and an excellent reproducibility and stability during multicycle calibrations carried out up to 1550°C, resulting in a record ultra‐high temperature sensing in film thermocouples. This facile thermocouple may open up a new way to measure high temperature in air or oxidation atmosphere accurately. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (PNCs) are promising fluorescent nanomaterials that have been employed in a wide range of areas. However, their applications in some specific fields, such as chem-/biosensing remain hampered due to their inherent instability to different external stimuli. Herein, we discover a novel mechanism that ethanol, a chemical that is generally thought to be detrimental to PNCs, could specifically initiate the in-situ crystallization of the precursor salts absorbed by paper fiber to yield standard CsPbBr 3 fluorescent PNCs. Based on systematical experimental verification, it is revealed that ethanol could mediate the interfacial interaction of the PNC precursor salts on the paper fiber to allow for this exceptional in-situ PNC crystallization process. Accordingly, a fluorescence turn-on mode paper sensor for rapid and high-sensitive expiratory alcohol detection is designed, which could fulfill the on-site visualized drink-driving screening requirement. Furthermore, the application of this new mechanism in multidimensional information encryption is also demonstrated. This work not only discovers a new mechanism for PNC crystallization but also expands the sensing application toolbox of PNCs. [Display omitted] • Ethanol can induce the crystallization of perovskite nanocrystals on paper fiber. • This is due to the on-paper interaction of the precursor salts induced by ethanol. • A paper sensor is developed for fluorescence turn-on expiratory alcohol sensing. • The sensor can reach the standard of drinking-driving screening. • This technique can also be used in information encryption. [ABSTRACT FROM AUTHOR]

(Mn 1.56 Co 0.96 Ni 0.48 O 4 ) 1 − x (LaMnO 3 ) x serial thin films have been synthesized on Si substrates through the chemical solution deposition method. The film crystal structures varied from a pure spinel phase to a mixed perovskite/spinel phase according to the increase in La concentration. Similarly, film density and surface roughness were improved with an increase in La concentration. According to the optical constant spectra of the composite thin films, two strong absorption structures appeared in the visible spectral range. Resistance–temperature curves indicated that all of the prepared thin films have negative temperature coefficient effects. In particular, the x = 0.5 film offered the lowest resistance and highest B 25/50 constant at 4022 K, compared with the remaining films. [ABSTRACT FROM AUTHOR]

Abstract: Ba0.5Sr0.5TiO3/Bi1.5Zn1.0Nb1.5O7 (BST/BZN) multilayer thin films were prepared on Pt/Al2O3 substrates by sol–gel method. The structure, morphology, and tunable dielectric properties of BST/BZN thin films were investigated. X-ray diffraction results showed that the structure of BST/BZN multilayer thin films was composed of a cubic BZN pyrochlore phase and a cubic BST perovskite phase. The diffraction pattern confirmed that there was no measurable reaction occurred between the BST and BZN layers. The field-emission scanning electron microscope (FESEM) showed that the surface of BST/BZN multilayer thin films was crack-free and compact. The dielectric constant and loss tangent of the BST/BZN multilayer thin films were 106 and 0.011 at 10kHz, respectively. The dielectric tunability was 10% under dc bias field of 355kV/cm at 10kHz. The medium dielectric constant, low loss tangent and tunability of the dielectric constant suggest that BST/BZN multilayer thin films have potential application for tunable microwave device applications. [Copyright &y& Elsevier]

PbZr0.52Ti0.48O3 (PZT) (52/48) thick films with thickness between 1–5 μ m have been prepared by a metallo-organic decomposition process modified by polymer, poly(vinyl acetate) (PVAc). It has been found that PVAc can increase the single-layer thickness of PZT films. The PZT films with a single-layer thickness over 0.3 μ m have been obtained. The crack-free PZT films annealed at 650–700°C for 3 min exhibit a pure perovskite phase and good electrical properties with dielectric constant between 800–1200, dielectric loss less than 5%, remnant polarization around 28 μ C/cm2 and coercive field less than 100 kV/cm. PZT thick films prepared in this study are promising materials for MEMS applications. [ABSTRACT FROM AUTHOR]

Polycrystalline and crack-free Pb0.94La0.04(Zr0.52Ti0.48)0.96Mn0.04O3 (PLMZT) thin films were prepared on LNO/Pt/SiO2/Si and fused silica substrates by a MOD method. PLMZT thin films possess a well-crystallized perovskite structure with (110) preferential orientation. Dielectric constant at 100 kHz is found to be 550. Coercive field and remanent polarization of PLMZT films are 145 kV/cm and 15 μC/cm2 respectively. Leakage current density of Au/PLMZT/LNO/Pt capacitor is 100–200 μA/cm2 at an applied electrical field of 300 kV/cm. The leakage current behavior is electrode-limited in nature. Remanent polarization and saturated polarization decrease about 18% after 108 cycles at 10 V and 100 Hz. The optical transmittance measurements indicate that the absorption edge of PLMZT films is about 285 nm. The band gap energy of PLMZT polycrystalline thin films is 3.82 eV. [ABSTRACT FROM AUTHOR]

We report the Ti-doping effects on the total magnetization of perovskite SmFe1-xTixO3 samples with x = 0, 0.1, 0.2, and 0.3. X-ray diffraction and Raman spectroscopy studies indicate that with the increase of Ti doping concentration, the lattice parameter b decreases and the oxygen octahedron is compressed along b axis. Such lattice distortion is also reflected by the changes of antisymmetric stretching mode and symmetric stretching mode of the oxygen octahedron through Raman spectra measurement. An enhancement of the interaction between Sm-4f and Fe-3d electrons is observed due to Ti-doping. This strong interplay between Sm-4f and Fe-3d electrons weakens the total magnetization and considerably suppresses the weak ferromagnetism of Fe sublattice starting from 260 K. [ABSTRACT FROM AUTHOR]

Researchers have demonstrated that BiFeO3 exhibits ferroelectric hysteresis but none have shown a strong ferromagnetic response in either bulk or thin film without significant structural or compositional modification. When remanent magnetisations are observed in BiFeO3 based thin films, iron oxide second phases are often detected. Using aberration-corrected scanning transmission electron microscopy, atomic resolution electron energy loss spectrum-mapping and quantitative energy dispersive X-ray spectroscopy analysis, we reveal the existence of a new Fe2O3-rich perovskite nanophase, with an approximate formula (Fe0.6Bi0.25Nd0.15)3+ Fe3+O3, formed within epitaxial Ti and Nd doped BiFeO3 perovskite films grown by pulsed laser deposition. The incorporation of Nd and Bi ions on the A-site and coherent growth with the matrix stabilise the Fe2O3-rich perovskite phase and preliminary density functional theory calculations suggest that it should have a ferrimagnetic response. Perovskite-structured Fe2O3 has been reported previously but never conclusively proven when fabricated at high-pressure high-temperature. This work suggests the incorporation of large A-site species may help stabilise perovskite-structured Fe2O3. This finding is therefore significant not only to the thin film but also to the high-pressure community. [ABSTRACT FROM AUTHOR]

In order to understand the complex phase symmetry and phase transitions, and to illustrate the microscopic mechanisms of high piezoelectricity, single crystals of a new ternary complex perovskite system, Pb(Mg 1/3 Nb 2/3 )O 3 -Bi(Zn 2/3 Nb 1/3 )O 3 -PbTiO 3 , are grown by the high temperature solution growth method and their domain structure, dielectric and ferro-/piezoelectric properties, and phase transformation behavior are investigated by various techniques. Different phase symmetries including the rhombohedral, tetragonal and monoclinic are found in these crystals, indicating that the composition of the crystals is close to the morphotropic phase boundary (MPB) region. Most interestingly, unusual phase transformation sequences of rhombohedral → monoclinic → cubic, and monoclinic → cubic are directly observed by polarized light microscopy and confirmed by the dielectric and birefringence results. Moreover, an ultrahigh piezoelectric coefficient d 33  ≈ 2000 pC/N is obtained in these crystals, making these crystals useful for applications as electromechanical transducers. The unusual phase transformation sequences and the high piezoelectric response are explained from the polarization rotation mechanism, which has been evidenced in this work. Based on these results, a temperature-composition phase diagram is established, which illustrates the complex phases present and their transformation behavior. These studies provide new insights into the intricate morphotropic phase symmetry and phase components in complex perovskite solid solutions, and a better understanding of the microscopic mechanisms of high piezoelectric response in relaxor-based piezocrystals, which in turn will be helpful for designing better piezoelectric single crystals. [ABSTRACT FROM AUTHOR]

In this study, a series of (Mn 1.56 Co 0.96 Ni 0.48 O 4 ) 1−x (LaMn 0.6 Al 0.4 O 3 ) x composite thin films was synthesized on silicon (100) substrates by chemical solution deposition method. Addition of LaMn 0.6 Al 0.4 O 3 aided in improvement in the film morphology and density, while keeping the electrical properties similar. More importantly, the cation redistribution, in particular, the Al 3+ entering into Mn 1.56 Co 0.96 Ni 0.48 O 4 grains, significantly facilitated the optical absorption in the wavelength range of 0.63–2 µm, which bears significant technological interests in designing and application of infrared detectors. [ABSTRACT FROM AUTHOR]

Abstract: Lead-free ferroelectric K0.5Na0.5NbO3 (KNN) films with different thicknesses were prepared by polyvinylpyrrolidone (PVP)-modified chemical solution deposition (CSD) method. The KNN films with thickness up to 4.9μm were obtained by repeating deposition-heating process. All KNN thick films exhibit single perovskite phase and stronger (110) peak when annealed at 650°C. The variation of dielectric constant with thickness indicates that there exists a critical thickness for the dielectric constant in the KNN films which should lie in 1.3–2.5μm. The similar trend is observed for the ferroelectric and piezoelectric properties of KNN films. Both the remnant polarization P r and the piezoelectric coefficient d 33 of KNN thick films increase with the film thickness and become saturated after the critical thickness. [Copyright &y& Elsevier]

CH 3 NH 3 PbI x Br 3− x thin films on FTO substrate were synthesized successfully. The crystal structure and optical properties of these films changed with different ratios of I − /Br − ions. The lattice parameters were reduced and the optical absorption edges were blue-shifted with the increasing ratio of Br - ions. The dielectric spectra have revealed that tetragonal CH 3 NH 3 PbI x Br 3 − x films at room temperature not only have a lower symmetry than cubic films, but also provide more electron transition energies. The mechanism is discussed correspondingly. [ABSTRACT FROM AUTHOR]

Mutiferroic materials like bismuth ferrite BiFeO 3 have attracted much interest in the last decade due to their promising potential for such applications as spintronics and magnetoelectric data storage devices. On the other hand, relaxor ferroelectrics have been intensively studied for their complex structures with quenched disorder and polar nanoregions which play an important role in their outstanding piezoelectric performance. Much less studied are the single-phase multiferroics that exhibit ferroelectric and/or magnetic relaxor behavior and the correlation between their structure and intricate magneto-electric interactions. In this work, we investigate the evolution of the structure and relaxor behavior in the solid solution between the complex perovskite multirelaxor Pb(Fe 2/3 W 1/3)O 3 [PFW] and canonical multiferroic BiFeO 3 [BFO], (1- x)PFW- x BFO (with a solubility limit of x = 0.30). The temperature dependences of the dielectric permittivity and loss tangent measured in the frequency range from 100 Hz to 1 MHz indicate characteristic relaxor ferroelectric properties for compositions of x ≤ 0.15, with a frequency-dependent dielectric permittivity peak and its temperature, T m , satisfying the Vogel-Fulcher law. Detailed studies of the evolution of the relaxor behavior with composition reveal that T m decreases firstly with a small amount (x = 0.05) of BFO substitution and then increases with further increase of BFO concentration. The degree of relaxor character, as defined by Δ T m [ T m (1 MHz) - T m (100 Hz)], increases monotonously with increasing BFO content, signifying an enhancement of relaxor behavior with BFO substitution, which is confirmed by the Lorenz-type quadratic variation of the static permittivity. A temperature - composition phase diagram is constructed in terms of the characteristic Burns temperature (T B) and freezing temperature (T f), which delimits a paraelectric state (PE) above T B , a non-ergotic relaxor state (NR) below T f , and an ergotic relaxor state (ER) in between. The observed enhancement of relaxor behavior is explained by an increase in the number and size distribution of polar nanoregions in the ER phase, resulting from increased compositional and charge disorders as a result of BFO substitution. The evolution of relaxor behavior and its microscopic mechanisms studied in this work are insightful for a better understanding the multirelaxor properties in multiferroics. Moreover, further substitution of BFO (x ≥ 0.2) flattens the permittivity curves and leads to a temperature-stable variation of high dielectric constant (≈ 103) in a wide temperature range, making the PFW-BFO solid solution attractive for such applications as high energy density capacitors. [ABSTRACT FROM AUTHOR]

Interesting magnetic behaviors, including negative magnetization, zero field fooled and field cooled exchange bias effects, have been observed in Eu 0.9 Pr 0.1 CrO 3 . The negative magnetization at low temperature results from the antiparallel coupling between the Pr 3+ moment and the canted moment of Cr 3+ sublattice. Left shift of zero field cooled M-H loops, and right shift of field cooled M-H loops have been observed, due to the growth and competition of two types of magnetic structures with G x F z (EuCrO 3 ) and G z F x (PrCrO 3 ) orderings under magnetic field. When the cooling field is high enough, the Pr 3+ moment is frozen antiparallel with the applied field during the cooling process, giving rise to a positive exchange bias (right shift of M - H ). However, when the cooling field is near zero, magnetic clusters with G x F z (EuCrO 3 ) or G z F x (PrCrO 3 ) orderings are formed and distribute randomly during the cooling process, and the net Pr 3+ moment get aligned along the applied field during the initial magnetization process to lower the Zeeman energy, and then negative exchange bias (left shift of M - H ) appears. [ABSTRACT FROM AUTHOR]

Complex perovskite solid solutions based on Bi(B′B″)O 3 -PbTiO 3 are potentially interesting ferroelectric and piezoelectric materials with high Curie temperature ( T C ). In this work, large-size (1- x )Bi(Zn 1/2 Ti 1/2 )O 3 - x PbTiO 3 (BZT-PT), and (1- x )Bi(Zn 2/3 Nb 1/3 )O 3 - x PbTiO 3 (BZN-PT) single crystals have been successfully grown by the high-temperature solution growth method and the top-cooled solution growth method. A comparative study of the (001)-oriented BZT-PT and BZN-PT crystals is carried out and significant differences are found in their structures and physical properties which are characterized by various techniques. The crystal structures of both crystals are refined to be of tetragonal symmetry by means of powder X-ray diffraction, but their local structures exhibit remarkable differences in terms of cationic displacements. The T C is determined to be around 572 °C and 424 °C for the BZT-PT and BZN-PT single crystals, respectively. The ferroic domain structures examined by polarized light microscopy based on optical crystallography are found to be different in the BZT-PT and BZN-PT crystals. The effects of domain structures on the different ferroelectric behaviors are investigated. The high T C and large coercive electric field, as well as the high remanent polarization of the BZT-PT and BZN-PT single crystals make them promising candidates for applications in high-power electromechanical transducers that can be operated in a wide temperature range. [ABSTRACT FROM AUTHOR]

We studied samarium-dysprosium rare-earth orthoferrites Sm x Dy 1−x FeO 3 (SDFO, x = 0–1, interval 0.1) with 11 different x concentration values. All of the SDFO single crystals were successfully grown by a hetero-seed and hetero-feed optical-floating-zone technique in flowing air. The XRD powder patterns illustrate that the lattice mismatch of two samples with Δx = 0.1 is about 0.1–0.2% in ac plane, which is considered appropriate for our hetero-seed and hetero-feed crystal growth. Thus, we could successfully grow the series of SDFO single crystals continuously, for example, the x = 0.8 single crystal was grown on the x = 0.7 seed rod. X-ray back-reflection Laue photographs indicate good quality of all the as-grown SDFO single crystals. Composition analysis of SDFO single crystals were conducted by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), which demonstrate the accurate cation stoichiometry for each crystal. Moreover, we show that such crystal system possesses particular anisotropic magnetic property. The hetero-seed growth method and hetero-feed single crystal relay growth based on optical-floating-zone technique will be useful in high-throughput crystal materials growth. [ABSTRACT FROM AUTHOR]

A series of DyFe 1- x In x O 3 ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1) polycrystalline samples have been prepared by the conventional solid reaction methods. The crystal structures, refined by the Fullprof, are found to be orthorhombic for 0 ≤ x ≤ 0.6 and hexagonal in the case of 0.7 ≤ x ≤ 1. The lattice constants are changed by the In ions doping, and a huge distortion of the magnetic sublattice was induced. The magnetization versus temperature curves are obtained for all the samples, at the temperature between 3 K and 300 K. The pure DyFeO 3 sample undergoes a spin reorientation transition at around 50 K, whereas the doped In 3+ ions significantly modify the phase transition. We reveal that such substitution retained the spin reorientation transition effect for x ≤ 0.8. We develop a formalism based on the molecular theory, giving explanation of the changes in the spin-reorientation temperature induced by the In-doping. Then, by performing density functional theory (DFT) calculation, we analyzed the magnetic phases for the hexagonal compounds. Furthermore, our findings indicate a type of Γ′ 4 - Γ′ 2 transition exists in the hexagonal Fe-In magnetic systems which directly point to a quasi-2 dimensional magnetic order. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent progress in bismuth-based high Curie temperature (T C) piezo-/ferroelectric perovskite (BPP) materials is reviewed. • The structure–property relationship of BPPs is established and discussed based on key crystal chemical and physical concepts. • Recent developments of BPPs for high-temperature electromechanical transduction applications are presented and evaluated. • Main existing issues of BPPs are identified and analyzed and their possible solutions are proposed. Piezo-/ferroelectric materials with high Curie temperature (T C) are widely needed in sensors, actuators and transducers which can be used for high-temperature (HT) electromechanical transduction applications. In recent years, remarkable progress has been made in bismuth-based piezo-/ferroelectric perovskite materials (BPPs). In this article, recent progress in high T C BPPs is reviewed. This review starts with an introduction to HT piezoelectrics and their applications. A detailed survey is then carried out on bismuth-based perovskites (BPs) with high T C. Material synthesis, doping effects and chemical modifications of the related solid solutions are examined. Based on this analysis, the structure–property relationship of these materials is established. In addition, recent developments of BPPs for HT electromechanical transduction applications are presented and evaluated. Lastly, some main existing issues are analyzed and their possible solutions are proposed. This article provides a comprehensive overview of the research and development of BPPs and offers some prospects towards making these materials a viable resource for the design and fabrication of electromechanical transducers with unique specifications, especially, high temperature, high frequency and high power, for a wide range of technological applications. [ABSTRACT FROM AUTHOR]

Perovskite bismuth ferrite-BFO (111) membranes, as a potential sensitive electrochemical sensor, are investigated for the detection of amino acids by molecular dynamics (MD) and density functional theory (DFT) techniques. For the detection mechanism of the ferromagnetic phase BFO (111) membrane, the cation bridge model indicates that there is a electronic signal amplification (0.01–0.09 V), due to the enhancement of Fe 3+ –COO − triple degeneracy orbit (t 2g ). It is an excellent detection sensitivity for various AAs that can be used to distinguish the surface charges. However, the Fe-d 7/2 momentum changes its orientation from upward to downward, on the anti-ferromagnetic phase BFO (111) membrane. The empty d 0 orbital degenerates to the O↓ orbital that weakens the Fe–O electron transfer rate, weakening the electronic signal (0.005–0.05 V). [ABSTRACT FROM AUTHOR]

Spontaneous polarization behaviors of hybrid perovskite CH 3 NH 3 PbI 3 film were confirmed by in situ PFM and spectroscopic ellipsometry. The film exhibits uniform spontaneous polarization and ferroelectric domain inversion performance. The fitted dielectric constants spectra agree well with the calculated ones. We attribute the spontaneous polarization behaviors of hybrid perovskite to lone pair electrons, and its outstanding photovoltaic performance partially originates from spontaneous polarization and plasma resonance. This report will facilitate understanding of the instinct physical essence of hybrid perovskite solar cells. [ABSTRACT FROM AUTHOR]

Abstract: Bismuth-doped strontium titanate thin films with pure perovskite phase have been successfully deposited on Pt (111)/Ti/SiO2/Si substrate by polymer-assisted sol–gel method. Poly(vinyl acetate) (PVAc) in precursor solution promoted the formation of perovskite phase during the heat treatment. SEM results revealed an increasing thickness from 40 to 80nm every single layer and a porous structure with the addition of PVAc. The addition of polymer made the dielectric constant decrease from 140 to 40 and the tunability slightly increase compared with films without polymer in precursor. [Copyright &y& Elsevier]

Three different SrFe x Ti 1− x O 3 ( x =0.001, 0.005 and 0.01) thin films were deposited on Pt/Ti/SiO 2 /Si (100) substrates by pulsed laser depositions at different substrate temperatures. The crystalline structure and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The dielectric properties of the films were studied by using Agilent 4980A LCR meter. The XRD results indicate that the films deposited above 650 °C shows a cubic perovskite structure with (110) orientation. Leakage current tests show that the conduction mechanism in the three different SrFe x Ti 1− x O 3 ( x =0.001, 0.005 and 0.01) thin films display ohmic behavior at low electric field and schottky emission at high electric field, respectively. [ABSTRACT FROM AUTHOR]

High Curie temperature piezoelectric materials have experienced huge development and widespread application in recent decades, especially for the application of novel perovskite xBiMeO 3 –(1− x ) PbTiO 3 solid–solutions family. Nowadays, with the fast increasing applications for integrated ferroelectrics, the high Curie temperature piezoelectric thin films have drawn considerable attention. In this paper we present the works on the preparation and electrical properties of 0.1BiYbO 3 –0.9PbTiO 3 thin films on Pt/TiO 2 /SiO 2 /Si (100) substrates by using pulsed laser deposition at 600 °C with different oxygen atmosphere pressure. The final samples were post-annealed at 700 °C for 10 min in a rapid thermal annealing (RTA) furnace. The phase structure and surface morphologies of the 0.1BiYbO 3 –0.9PbTiO 3 thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The frequency dependent dielectric properties were measured by an Agilent4980A LCR meter. Finally, the piezoelectric properties of the films were tested by using piezoelectric force microscopy (PFM). [ABSTRACT FROM AUTHOR]