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We identify a first‐order, isosymmetric transition between a ferrielectric (FiE) and ferroelectric (FE) state in A‐site ordered LaScO3/BiScO3 and LaInO3/BiInO3 superlattices. Such a previously unreported ferroic transition is driven by the easy switching of cation displacements without changing the overall polarization direction or crystallographic symmetry. Epitaxial strains less than 2% are predicted to be sufficient to traverse the phase boundary, across which we capture a ≈5× increase in electric polarization. Unlike conventional Pb‐based perovskite ceramics with a morphotropic phase boundary (MPB) that show polarization rotation, we predict an electromechanical response up to 102 pC/N in the vicinity of the FiE‐FE phase boundary due to polarization switching without any change in symmetry. We propose this transition as an alternative ferroic transition to obtain a piezoelectric response, with the additional advantage of occurring in benign chemistries without chemical disorder. 相似文献
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Saidur R. Bakaul Jaegyu Kim Seungbum Hong Mathew J. Cherukara Tao Zhou Liliana Stan Claudy R. Serrao Sayeef Salahuddin Amanda K. Petford-Long Dillon D. Fong Martin V. Holt 《Advanced materials (Deerfield Beach, Fla.)》2020,32(4):1907036
Ferroelectric domain walls in single-crystal complex oxide thin films are found to be orders of magnitude slower when the interfacial bonds with the heteroepitaxial substrate are broken to create a freestanding film. This drastic change in domain wall kinetics does not originate from the alteration of epitaxial strain; rather, it is correlated with the structural ripples at mesoscopic length scale and associated flexoelectric effects induced in the freestanding films. In contrast, the effects of the bond-breaking on the local static ferroelectric properties of both top and bottom layers of the freestanding films, such as domain wall width and spontaneous polarization, are modest and governed by the change in epitaxy-induced compressive strain. 相似文献
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Electric and Mechanical Switching of Ferroelectric and Resistive States in Semiconducting BaTiO3–δ Films on Silicon 下载免费PDF全文
Andrés Gómez José Manuel Vila‐Fungueiriño Rahma Moalla Guillaume Saint‐Girons Jaume Gázquez María Varela Romain Bachelet Martí Gich Francisco Rivadulla Adrián Carretero‐Genevrier 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(39)
Materials that can couple electrical and mechanical properties constitute a key element of smart actuators, energy harvesters, or many sensing devices. Within this class, functional oxides display specific mesoscale responses which often result in great sensitivity to small external stimuli. Here, a novel combination of molecular beam epitaxy and a water‐based chemical‐solution method is used for the design of mechanically controlled multilevel device integrated on silicon. In particular, the possibility of adding extra functionalities to a ferroelectric oxide heterostructure by n‐doping and nanostructuring a BaTiO3 thin film on Si(001) is explored. It is found that the ferroelectric polarization can be reversed, and resistive switching can be measured, upon a mechanical load in epitaxial BaTiO3?δ /La0.7Sr0.3MnO3/SrTiO3/Si columnar nanostructures. A flexoelectric effect is found, stemming from substantial strain gradients that can be created with moderate loads. Simultaneously, mechanical effects on the local conductivity can be used to modulate a nonvolatile resistive state of the BaTiO3?δ heterostructure. As a result, three different configurations of the system become accessible on top of the usual voltage reversal of polarization and resistive states. 相似文献
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为了提高孔洞结构聚丙烯(cellular PP)铁电驻极体的压电性能,采用高压气体膨化技术对材料进行了改性处理,并利用准静态和干涉仪测量方法,对经处理的cellular PP铁电驻极体薄膜的压电效应进行了研究.结果表明:气体膨化工艺能够明显提高cellular PP铁电驻极体薄膜的压电活性:这种突出的压电活性源干膨化膜杨氏模量Y的降低和电极化能力的提高;压电系数d33随频率的增加呈现下降趋势:从0.01 Hz下的1200 pC/N降低到共振频率附近的350 pC/N;对于不同参数处理的样品,它们的共振频率在150~400 kHz;大多数样品的d33在0.2~10 kPa的范围内没有明显的变化,但是高于10 kPa,d33随之下降;cellular PP铁电驻极体薄膜d33的热稳定性与非孔洞型PP驻极体薄膜的电荷储存热稳定性相当. 相似文献
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David Pesquera Eric Parsonnet Alexander Qualls Ruijuan Xu Andrew J. Gubser Jieun Kim Yizhe Jiang Gabriel Velarde Yen-Lin Huang Harold Y. Hwang Ramamoorthy Ramesh Lane W. Martin 《Advanced materials (Deerfield Beach, Fla.)》2020,32(43):2003780
Strain engineering in perovskite oxides provides for dramatic control over material structure, phase, and properties, but is restricted by the discrete strain states produced by available high-quality substrates. Here, using the ferroelectric BaTiO3, production of precisely strain-engineered, substrate-released nanoscale membranes is demonstrated via an epitaxial lift-off process that allows the high crystalline quality of films grown on substrates to be replicated. In turn, fine structural tuning is achieved using interlayer stress in symmetric trilayer oxide-metal/ferroelectric/oxide-metal structures fabricated from the released membranes. In devices integrated on silicon, the interlayer stress provides deterministic control of ordering temperature (from 75 to 425 °C) and releasing the substrate clamping is shown to dramatically impact ferroelectric switching and domain dynamics (including reducing coercive fields to <10 kV cm−1 and improving switching times to <5 ns for a 20 µm diameter capacitor in a 100-nm-thick film). In devices integrated on flexible polymers, enhanced room-temperature dielectric permittivity with large mechanical tunability (a 90% change upon ±0.1% strain application) is demonstrated. This approach paves the way toward the fabrication of ultrafast CMOS-compatible ferroelectric memories and ultrasensitive flexible nanosensor devices, and it may also be leveraged for the stabilization of novel phases and functionalities not achievable via direct epitaxial growth. 相似文献
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Semiconducting Films: Electric and Mechanical Switching of Ferroelectric and Resistive States in Semiconducting BaTiO3–δ Films on Silicon (Small 39/2017) 下载免费PDF全文
Andrés Gómez José Manuel Vila‐Fungueiriño Rahma Moalla Guillaume Saint‐Girons Jaume Gázquez María Varela Romain Bachelet Martí Gich Francisco Rivadulla Adrián Carretero‐Genevrier 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(39)
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Enhanced Photoelectrochemical Performance in Reduced Graphene Oxide/BiFeO3 Heterostructures 下载免费PDF全文
Yan Ren Feng Nan Lu You Yang Zhou Yanyan Wang Junling Wang Xiaodong Su Mingrong Shen Liang Fang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(16)
BiFeO3 (BFO)‐based ferroelectrics have been proved to be visible‐light‐driven photoelectrodes for O2 production. However, the hitherto reported photoelectrochemical performances remain inferior to meet the requirements for any applications. Besides, expensive noble metals (Ag, Au) are commonly required to achieve high photoelectric conversion efficiency. Here, the significant enhancements of photoelectrochemical performance is reported by fabricating a noble‐metal‐free reduced graphene oxide (RGO)/BFO composite film via a simple and cost‐effective solution process. The optimized RGO/BFO composite film exhibits a 600% improvement of the short‐circuit photocurrent density compared to that of the pristine BFO, and also outperforms the noble‐metal/BFO cells under the same reaction conditions. Furthermore, the incident photon‐to‐current efficiency of the optimized RGO/BFO sample shows threefold enhancement. This study delivers a facile and low‐cost approach to preparing 2D materials/ferroelectric heterostructures and offers a promising pathway to boost the performance of semiconducting ferroelectric photoelectrodes. 相似文献
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Amey Apte Kosar Mozaffari Farnaz Safi Samghabadi Jordan A. Hachtel Long Chang Sandhya Susarla Juan Carlos Idrobo David C. Moore Nicholas R. Glavin Dmitri Litvinov Pradeep Sharma Anand B. Puthirath Pulickel M. Ajayan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(24):2000006
Since graphene, a variety of 2D materials have been fabricated in a quest for a tantalizing combination of properties and desired physiochemical behavior. 2D materials that are piezoelectric, i.e., that allow for a facile conversion of electrical energy into mechanical and vice versa, offer applications for sensors, actuators, energy harvesting, stretchable and flexible electronics, and energy storage, among others. Unfortunately, materials must satisfy stringent symmetry requirements to be classified as piezoelectric. Here, 2D ultrathin single-crystal molybdenum oxide (MoO2) flakes that exhibit unexpected piezoelectric-like response are fabricated, as MoO2 is centrosymmetric and should not exhibit intrinsic piezoelectricity. However, it is demonstrated that the apparent piezoelectricity in 2D MoO2 emerges from an electret-like behavior induced by the trapping and stabilization of charges around defects in the material. Arguably, the material represents the first 2D electret material and suggests a route to artificially engineer piezoelectricity in 2D crystals. Specifically, it is found that the maximum out-of-plane piezoresponse is 0.56 pm V−1, which is as strong as that observed in conventional 2D piezoelectric materials. The charges are found to be highly stable at room temperature with a trapping energy barrier of ≈2 eV. 相似文献
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采用顶部籽晶法生长了一系列不同组分的高居里温度铌镥酸铅-钛酸铅[(1-x)Pb(Lu1/2Nb1/2)O3-xPbTiO3 (PLN-xPT)]铁电晶体。该晶体在三方相区域表现出典型的介电弛豫特性, 不同组分的晶体表现出了较高的居里温度; 基于介电和结构测试结果, 得到了该体系的低温二元体系相图, 在相图中存在一个准同型相界区域(MPB), 其组分位于x = 0.49~0.51; 利用偏光显微镜分析晶体电畴结构得到和X射线粉末衍射测试结果吻合的相结构; 电学性能测试结果表明不同组分的晶体性能差异较大。组分位于MPB附近的晶体表现出优异的压电性能, 如x = 0.49时, 居里温度Tc = 360℃, 压电常数d33 > 1600 pC/N。处于MPB附近的晶体存在较大的矫顽Ec >10kV/cm, 一些组分晶体的三方–四方相变温度TRT > 200℃。结果表明高的居里温度及优异的压电性能使二元铌镥酸铅-钛酸铅晶体具有更大的温度应用范围及更广阔的应用前景。 相似文献
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Qiang Pan Zhi‐Bo Liu Han‐Yue Zhang Wan‐Ying Zhang Yuan‐Yuan Tang Yu‐Meng You Peng‐Fei Li Wei‐Qiang Liao Ping‐Ping Shi Rong‐Wei Ma Ru‐Yuan Wei Ren‐Gen Xiong 《Advanced materials (Deerfield Beach, Fla.)》2017,29(29)
An outstanding advantage of inorganic ceramic ferroelectrics is their usability in the polycrystalline ceramic or thin film forms, which has dominated applications in the ferroelectric, dielectric, and piezoelectric fields. Although the history of ferroelectrics began with the molecular ferroelectric Rochelle salt in 1921, so far there have been very few molecular ferroelectrics, with lightweight, flexible, low‐cost, and biocompatible superior properties compared to inorganic ceramic ferroelectrics, that can be applied in the polycrystalline form. Here, a multiaxial molecular ferroelectric, guanidinium perchlorate ([C(NH2)3]ClO4), with a record‐high phase transition temperature of 454 K is presented. It is the rectangular polarization–electric field (P –E ) hysteresis loops recorded on the powder and thin film samples (with respective large P r of 5.1 and 8.1 µC cm?2) that confirm the ferroelectricity of [C(NH2)3]ClO4 in the polycrystalline states. Intriguingly, after poling, the piezoelectric coefficient (d 33) of the powder sample shows a significant increase from 0 to 10 pC N?1, comparable to that of LiNbO3 single crystal (8 pC N?1). This is the first time that such a phenomenon has been observed in molecular ferroelectrics, indicating the great potential of molecular ferroelectrics being used in the polycrystalline form like inorganic ferroelectrics, as well as being viable alternatives or supplements to conventional ceramic ferroelectrics. 相似文献
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Ferroelectric Materials: Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead‐Free ABO3 Ferroelectrics (Adv. Mater. 29/2015) 下载免费PDF全文
Abhijit Pramanick Mads R. V. Jørgensen Souleymane O. Diallo Andrew D. Christianson Jaime A. Fernandez‐Baca Christina Hoffmann Xiaoping Wang Si Lan Xun‐Li Wang 《Advanced materials (Deerfield Beach, Fla.)》2015,27(29):4329-4329