Artykuły w czasopismach: „Ferroelectrics”

1

Zhang, Xinhao, i Bo Peng. "The twisted two-dimensional ferroelectrics". Journal of Semiconductors 44, nr 1 (1.01.2023): 011002. http://dx.doi.org/10.1088/1674-4926/44/1/011002.

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Abstract Since the beginning of research on two-dimensional (2D) materials, a few numbers of 2D ferroelectric materials have been predicted or experimentally confirmed, but 2D ferroelectrics as necessary functional materials are greatly important in developing future electronic devices. Recent breakthroughs in 2D ferroelectric materials are impressive, and the physical and structural properties of twisted 2D ferroelectrics, a new type of ferroelectric structure by rotating alternating monolayers to form an angle with each other, have attracted widespread interest and discussion. Here, we review the latest research on twisted 2D ferroelectrics, including Bernal-stacked bilayer graphene/BN, bilayer boron nitride, and transition metal dichalcogenides. Finally, we prospect the development of twisted 2D ferroelectrics and discuss the challenges and future of 2D ferroelectric materials.

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WANG, JIE, i TONG-YI ZHANG. "PHASE FIELD STUDY OF POLARIZATION VORTEX IN FERROELECTRIC NANOSTRUCTURES". Journal of Advanced Dielectrics 02, nr 02 (kwiecień 2012): 1241002. http://dx.doi.org/10.1142/s2010135x12410020.

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Ferroelectric nanostructures are attracting considerable attention due to their unusual physical properties and potential applications in memory devices and nanoelectromechanical systems. It has been found that low-dimensional ferroelectrics, such as ferroelectric nanodots, ferroelectric nanotubes and ferroelectric thin films, exhibit polarization vortices or vortex-like domain structures due to the strong depolarization field and the size effect. The polarization vortex is regarded as a new toroidal order in ferroelectrics which is different from the rectilinear order of polarization. The vortex states of polarization are bistable and can be switched from one state to the other, which holds the potential application in next generation ferroelectric memories. This paper briefly reviews the recent work on the phase field studies of polarization vortex in ferroelectric nanostructures. The homogeneous bulk thermodynamics of ferroelectrics is first introduced based on the Landau–Devonshire theory. To describe the inhomogeneous polarization distribution in ferroelectrics, the phase field model including interface thermodynamics is then presented in the form of time-dependent Ginzburg–Landau equations.

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MA, WENHUI. "FLEXOELECTRIC EFFECT IN FERROELECTRICS". Functional Materials Letters 01, nr 03 (grudzień 2008): 235–38. http://dx.doi.org/10.1142/s179360470800037x.

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Flexoelectric effect and its influence on the application of multifunctional ferroelectrics have been investigated. Theory of flexoelectric coupling has indicated that mechanical strain gradient can impact polarization in a way analogous to electric field. Experimentally, magnitudes of the flexoelectric coefficients have been measured in ferroelectric, incipient ferroelectric and relaxor ferroelectric perovskites. Present data of flexoelectricity suggests that such unconventional electromechanical coupling could make unique contribution to properly engineered ferroelectric thin films and nanostructures. Flexoelectric effect is expected to intensify at small dimensions and get large enough at nanoscale to significantly impact phase transition and functional response in ferroelectrics.

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Huyan, Huaixun, Linze Li, Christopher Addiego, Wenpei Gao i Xiaoqing Pan. "Structures and electronic properties of domain walls in BiFeO3 thin films". National Science Review 6, nr 4 (1.07.2019): 669–83. http://dx.doi.org/10.1093/nsr/nwz101.

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Abstract Domain walls (DWs) in ferroelectrics are atomically sharp and can be created, erased, and reconfigured within the same physical volume of ferroelectric matrix by external electric fields. They possess a myriad of novel properties and functionalities that are absent in the bulk of the domains, and thus could become an essential element in next-generation nanodevices based on ferroelectrics. The knowledge about the structure and properties of ferroelectric DWs not only advances the fundamental understanding of ferroelectrics, but also provides guidance for the design of ferroelectric-based devices. In this article, we provide a review of structures and properties of DWs in one of the most widely studied ferroelectric systems, BiFeO3 thin films. We correlate their conductivity and photovoltaic properties to the atomic-scale structure and dynamic behaviors of DWs.

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Ke, Changming, Jiawei Huang i Shi Liu. "Two-dimensional ferroelectric metal for electrocatalysis". Materials Horizons 8, nr 12 (2021): 3387–93. http://dx.doi.org/10.1039/d1mh01556g.

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Two dimensional ferroelectrics with out-of-plane polarization can be engineered via layer stacking to a genuine ferroelectric metal. These 2D ferroelectrics can serve as electrically-tunable, high-quality switchable electrocatalysts.

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Kimura, Tsuyoshi. "Current Progress of Research on Magnetically-induced Ferroelectrics". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C6. http://dx.doi.org/10.1107/s2053273314099938.

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Among several different types of magnetoelectric multiferroics, "magnetically-induced ferroelectrics" in which ferroelectricity is induced by complex spin orders, such as spiral orders, exhibit giant direct magnetoelectric effects, i.e., remarkable changes in electric polarization in response to a magnetic field. Not a few spin-driven ferroelectrics showing the magnetoelectric effects have been found in the past decade.[1] However, their induced ferroelectric polarization is much smaller than that in conventional ferroelectrics and mostly develops only at temperatures much lower than room temperature. Thus, the quest for spin-driven ferroelectrics with room temperature operation and/or robust ferroelectric polarization is still a major challenge in magnetoelectric multiferroics research. In this presentation, I will begin with introducing the background of research on magnetically-induced ferroelectrics, and present the following current progress. Recently, some hexaferrites have been found to show direct magnetoelectric effects at room temperature and relatively low magnetic fields.[2] Furthermore these hexferrites show inverse magnetoelectric effects, that is, induction of magnetization by applying electric fields, at room temperature. The results represented an important step toward practical applications using the magnetoelectric effect in spin-driven ferroelectrics. This presentation introduces magnetism and magnetoelectricity of several types of hexaferrites which show magnetoelectric effect at temperatures above room temperature. In addition, I will also introduce our recent work on magnetoelectric perovskite manganites with large magnetically-induced ferroelectric polarization which is comparable to that in conventional ferroelectrics. This work has been done in collaboration with T. Aoyam, K. Haruki, K. Okumura, A. Miyake, K. Shimizu, and S. Hirose.

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Liu, Meiying, Jingjing Liang, Yadong Tian i Zhiliang Liu. "Post-synthetic modification within MOFs: a valuable strategy for modulating their ferroelectric performance". CrystEngComm 24, nr 4 (2022): 724–37. http://dx.doi.org/10.1039/d1ce01567b.

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It is a great route designing new MOF ferroelectrics to enrich the scope of ferroelectrics or improving the ferroelectric performance to enhance the opportunity of applications through the strategy of post-synthetic modification (PSM).

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Gao, Liang, Ben-Lin Hu, Linping Wang, Jinwei Cao, Ri He, Fengyuan Zhang, Zhiming Wang, Wuhong Xue, Huali Yang i Run-Wei Li. "Intrinsically elastic polymer ferroelectric by precise slight cross-linking". Science 381, nr 6657 (4.08.2023): 540–44. http://dx.doi.org/10.1126/science.adh2509.

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Ferroelectrics are an integral component of the modern world and are of importance in electrics, electronics, and biomedicine. However, their usage in emerging wearable electronics is limited by inelastic deformation. We developed intrinsically elastic ferroelectrics by combining ferroelectric response and elastic resilience into one material by slight cross-linking of plastic ferroelectric polymers. The precise slight cross-linking can realize the complex balance between crystallinity and resilience. Thus, we obtained an elastic ferroelectric with a stable ferroelectric response under mechanical deformation up to 70% strain. This elastic ferroelectric exerts potentials in applications related to wearable electronics, such as elastic ferroelectric sensors, information storage, and energy transduction.

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PARK, Min Hyuk. "Renaissance of Ferroelectric Memories: Can They Be a Game-changer?" Physics and High Technology 30, nr 9 (30.09.2021): 16–23. http://dx.doi.org/10.3938/phit.30.028.

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Ferroelectric memories have been studied for ∼60 years since their first suggestion in 1952. The material properties of ferroelectrics are considered ideal for universal memories with the availability of electrical program/erase and read processes. However, challenges in the physical scaling down of bulk ferroelectric materials were a critical hurdle for the success of ferroelectric materials. In 2011, ferroelectricity in HfO2-based thin film was first reported, and this unexpected discovery revived research on ferroelectric memories. In this review, the properties, history, and applications of HfO2-based ferroelectrics are reviewed, and a perspective on semiconductor devices based on them is provided.

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Chen, Zibin, Fei Li, Qianwei Huang, Fei Liu, Feifei Wang, Simon P. Ringer, Haosu Luo, Shujun Zhang, Long-Qing Chen i Xiaozhou Liao. "Giant tuning of ferroelectricity in single crystals by thickness engineering". Science Advances 6, nr 42 (październik 2020): eabc7156. http://dx.doi.org/10.1126/sciadv.abc7156.

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Thickness effect and mechanical tuning behavior such as strain engineering in thin-film ferroelectrics have been extensively studied and widely used to tailor the ferroelectric properties. However, this is never the case in freestanding single crystals, and conclusions from thin films cannot be duplicated because of the differences in the nature and boundary conditions of the thin-film and freestanding single-crystal ferroelectrics. Here, using in situ biasing transmission electron microscopy, we studied the thickness-dependent domain switching behavior and predicted the trend of ferroelectricity in nanoscale materials induced by surface strain. We discovered that sample thickness plays a critical role in tailoring the domain switching behavior and ferroelectric properties of single-crystal ferroelectrics, arising from the huge surface strain and the resulting surface reconstruction. Our results provide important insights in tuning polarization/domain of single-crystal ferroelectric via sample thickness engineering.

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11

Ricinschi, Dan, i Eisuke Tokumitsu. "Multiagent Strategic Interaction Based on a Game Theoretical Approach to Polarization Reversal in Ferroelectric Capacitors". Journal of Advanced Computational Intelligence and Intelligent Informatics 15, nr 7 (20.09.2011): 806–12. http://dx.doi.org/10.20965/jaciii.2011.p0806.

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Ferroelectric materials are currently integrated in nonvolatile memory devices, whose principle is to allocate 0 and 1 logic bits to opposite orientations of the spontaneous polarization vector that are permitted by crystal symmetry. Typically made of randomly oriented grains, ferroelectrics tend to split into domains, according to the experienced sequence of electric fields, thermal treatments and any structural imperfections. On this background, we attempt to formulate new principles of exploiting such structural and operational degrees of freedom for unconventional applications of ferroelectrics. In this paper, we envision a new paradigm of ferroelectrics as processors of multiagent strategic interactions, employing unconventional mathematical tools (normally used for optimizing the decision-making process of rational human subjects) for analyzing ferroelectric capacitors’ response to combinatorial pulses. Specifically, we quantify the way microscopic assembly laws of the ferroelectric material mediate the amount of polarization reversed by two electrical pulses using the mathematical theory of games, applied to a strategic interaction between two hypothetical players impersonated by the two pulses. Such socially meaningful implementations of applied mathematics concepts onto an oxide material substrate are worth to consider in view of artificial intelligence applications, adding ferroelectrics to the class of media able to perform unconventional computations.

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12

YANG, Chan-Ho. "New Horizons for Ferroelectrics". Physics and High Technology 30, nr 9 (30.09.2021): 24–30. http://dx.doi.org/10.3938/phit.30.029.

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Since the discovery of ferroelectricity in 1920, dielectric research has provided a variety of fundamental physics problems and sustainable applications. Advances in synthesis and nanoscale characterization, along with theoretical innovations, have made ferroelectrics more versatile. In this perspective, we discuss several directions for future ferroelectric research in terms of flexoelectricity, ferroelectric topology, and lattice defects, as well as cooperation with associated fields.

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Pavlenko, Maksim A., Franco Di Rino, Leo Boron, Svitlana Kondovych, Anaïs Sené, Yuri A. Tikhonov, Anna G. Razumnaya, Valerii M. Vinokur, Marcelo Sepliarsky i Igor A. Lukyanchuk. "Phase Diagram of a Strained Ferroelectric Nanowire". Crystals 12, nr 4 (24.03.2022): 453. http://dx.doi.org/10.3390/cryst12040453.

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Ferroelectric materials manifest unique dielectric, ferroelastic, and piezoelectric properties. A targeted design of ferroelectrics at the nanoscale is not only of fundamental appeal but holds the highest potential for applications. Compared to two-dimensional nanostructures such as thin films and superlattices, one-dimensional ferroelectric nanowires are investigated to a much lesser extent. Here, we reveal a variety of the topological polarization states, particularly the vortex and helical chiral phases, in loaded ferroelectric nanowires, which enable us to complete the strain–temperature phase diagram of the one-dimensional ferroelectrics. These phases are of prime importance for optoelectronics and quantum communication technologies.

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Mikolajick, Thomas, Stefan Müller, Tony Schenk, Ekaterina Yurchuk, Stefan Slesazeck, Uwe Schröder, Stefan Flachowsky i in. "Doped Hafnium Oxide – An Enabler for Ferroelectric Field Effect Transistors". Advances in Science and Technology 95 (październik 2014): 136–45. http://dx.doi.org/10.4028/www.scientific.net/ast.95.136.

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Ferroelectrics are very interesting materials for nonvolatile data storage due to the fact that they deliver very low power programming operation combined with nonvolatile retention. For 60 years researchers have been inspired by these fascinating possibilities and have tried to build ferroelectric memory devices that can compete with mainstream technologies in their respective time. The progress of the current concepts is limited by the low compatibility of ferroelectrics like PZT with CMOS processing. Therefore, PZT or SBT based 1T1C ferroelectric memories are not scaling below 130 nm and 1T ferroelectric FETs based on the same materials are still struggling with low retention and very thick memory stacks. Hafnium oxide, a standard material in sub 45 nm CMOS, can show ferroelectric hysteresis with promising characteristics. By adding a few percent of silicon and annealing the films in a mechanically confined manner. Boescke et al. demonstrated ferroelectric hysteresis in hafnium oxide for the first time. Recently, a large number of dopants including Y, Al, Gd and Sr have been used to induce ferroelectricity in HfO2. This paper reviews the current status of hafnium oxide based ferroelectrics, its application to field effect transistors and puts this approach into a wider context of earlier developments in the field.

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15

Sidorkin, A. S., B. M. Darinskii, S. D. Milovidova, L. N. Korotkov i G. S. Grigoryan. "Effect of the Component Interaction on the Phase Transitions and Dielectric Properties of Ferroelectric Composites". Кристаллография 68, nr 5 (1.09.2023): 832–40. http://dx.doi.org/10.31857/s0023476123600519.

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The dielectric properties of ferroelectric composites and the specific features of the phase transitions occurring in them are discussed in comparison with the homogeneous ferroelectrics incorporated in the composites studied. The components incorporated into the dielectric matrix of ferroelectrics are considered to be triglycine sulfate, single crystals of potassium dihydrogen phosphate group, sodium nitrite, and perovskite-type materials. The factors changing the temperature range of polar phase existence in the ferroelectric composites under consideration are revealed and discussed. The results of the studies performed in this field are briefly reviewed. The work with the ferroelectric components incorporated into the aforementioned composites was performed in cooperation and under the guidance of L.A. Shuvalov.

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Liu, Arthur Haozhe, Lisa Luhong Wang i Lingping Kong. "Relaxor ferroelectrics materials under high pressure". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C979. http://dx.doi.org/10.1107/s2053273314090202.

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The rich phase diagrams from both relaxor and normal ferroelectrics under high pressure, stimulate us to study the pressure effect on the relaxor-PbTiO3 (PT) systems, to check whether the high pressure cubic structure will turn to low symmetry structure upon strong compression is the common behaviors for relaxor ferroelectrics materials. Furthermore, a complete phase diagram study of pressure-temperature effect on structure will allow us to explore the limitation on applications of relaxor-PT material devices under harsh environment involving in high pressure and high temperature conditions. Structure evolution and phase transition of several solid solution ferroelectrics, such as Pb(YbNb)O3-PT (PYN-PT), have been studied using in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy techniques under high pressure and high temperature conditions. XRD results show pressure induced phase transitions to a cubic phase, while the persistence of Raman spectroscopy in the full pressure range indicates its local distortion. A pressure-temperature phase diagram is further constructed to determine the stability region of the ferroelectric phase. The results provide useful guidance for the applications of this kind of high Curie temperature ferroelectric crystal under extreme conditions, and extra clue to synthesis of ferroelectric materials with tailored properties.

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Le, Minh-Tien, Phuong-Linh Do, Van-Tuan Le, Dang Thi Hong Hue, Van-Hai Dinh, Trong-Giang Nguyen i Le Van Lich. "The origin of piezoelectric enhancement in compositionally graded ferroelectrics with sinusoidal variation". Applied Physics Letters 121, nr 16 (17.10.2022): 162905. http://dx.doi.org/10.1063/5.0115482.

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The direct piezoelectric effect of [Formula: see text] Ba1− xSr xTiO3 graded ferroelectrics, whose compositions change in a sinusoidal form, is investigated via an extended phase-field method. The obtained results demonstrate that the piezoelectric coefficient can be significantly enhanced by controlling the amplitude of sinusoidal variation. The origin of piezoelectric enhancement is investigated by considering the formation of polarization domain structures and their behaviors under strain. Although a ferroelectric tetragonal phase or a paraelectric cubic phase primarily form in homogeneous Ba1− xSr xTiO3 ferroelectrics with a different content x, interestingly, an unusual ferroelectric monoclinic phase can be formed in compositionally graded ferroelectrics, giving rise to the coexistence of multiple phases. The monoclinic phase emerges as a result of the process that reduces built-in electric potential induced by a large gradient of polarization. In turn, the formation of the monoclinic phase gives rise to transient zones that make the polarization field more susceptible to external strains, thereby enhancing the piezoelectric response. We further demonstrate that the piezoelectric enhancement strongly depends on the volume fraction of the monoclinic phase in compositionally graded ferroelectrics, suggesting a route for the rational design of polarization domains and piezoelectric effects.

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Shang, Jing, Congxin Xia, Chun Tang, Chun Li, Yandong Ma, Yuantong Gu i Liangzhi Kou. "Mechano-ferroelectric coupling: stabilization enhancement and polarization switching in bent AgBiP₂Se₆ monolayers". Nanoscale Horizons 6, nr 12 (2021): 971–78. http://dx.doi.org/10.1039/d1nh00402f.

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Two-dimensional ferroelectrics are core candidates for the development of next-generation non-volatile storage devices, which rely highly on ferroelectric stability and feasible approaches to manipulate the ferroelectric polarization and domain.

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Sayer, M., Z. Wu, C. V. R. Vasant Kumar, D. T. Amm i E. M. Griswold. "Ferroelectrics for semiconductor devices". Canadian Journal of Physics 70, nr 10-11 (1.10.1992): 1159–70. http://dx.doi.org/10.1139/p92-188.

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The integration of thin film ferroelectrics with silicon processing is being implemented for various types of devices. The technology is based on the sputtering or chemical deposition of lead-based perovskites such as lead zirconate titanate. Factors concerned with the integration of ferroelectric films with semiconductor processing are described. Major interests in Canada include nonvolatile ferroelectric random access memories for high-speed digital or long-term analog memory applications, high-density capacitors, electro-optic switches, and a wide range of sensors and actuators integrated into silicon.

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Rüdiger, Andreas, i Rainer Waser. "Nanoscale Ferroelectrics". Advances in Science and Technology 45 (październik 2006): 2392–99. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2392.

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Ferroelectrics are among the most advanced materials for non-volatile storage applications. Their two thermodynamically equivalent groundstates of spontaneous polarization can be toggled between by an external electric field. We present recent progress in the fabrication, registration, manipulation and characterization of nanoscale ferroelectrics. Chemical solution deposition is adapted to a pre-registration process by e-beam lithography to fabricate registered ferroelectric nanostructures below 100 nm width. A post-processing by chemical mechanical polishing either for embedded or free grains modifies the aspect ratio thus controlling the coercive field distribution of nanoferroelectrics. We also discuss some very recent findings of the complex interaction of field and piezoelectric tensor in a real piezoresponse force microscope. This method requires a comprehensive treatment of all contributions to tell apart extrinsic from intrinsic effects.

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Li, Peng-Fei, Wei-Qiang Liao, Yuan-Yuan Tang, Wencheng Qiao, Dewei Zhao, Yong Ai, Ye-Feng Yao i Ren-Gen Xiong. "Organic enantiomeric high-Tcferroelectrics". Proceedings of the National Academy of Sciences 116, nr 13 (8.03.2019): 5878–85. http://dx.doi.org/10.1073/pnas.1817866116.

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For nearly 100 y, homochiral ferroelectrics were basically multicomponent simple organic amine salts and metal coordination compounds. Single-component homochiral organic ferroelectric crystals with high-Curie temperature (Tc) phase transition were very rarely reported, although the first ferroelectric Rochelle salt discovered in 1920 is a homochiral metal coordination compound. Here, we report a pair of single-component organic enantiomorphic ferroelectrics, (R)-3-quinuclidinol and (S)-3-quinuclidinol, as well as the racemic mixture (Rac)-3-quinuclidinol. The homochiral (R)- and (S)-3-quinuclidinol crystallize in the enantiomorphic-polar point group 6 (C6) at room temperature, showing mirror-image relationships in vibrational circular dichroism spectra and crystal structure. Both enantiomers exhibit 622F6-type ferroelectric phase transition with as high as 400 K [above that of BaTiO3(Tc= 381 K)], showing very similar ferroelectricity and related properties, including sharp step-like dielectric anomaly from 5 to 17, high saturation polarization (7 μC/cm2), low coercive field (15 kV/cm), and identical ferroelectric domains. Their racemic mixture (Rac)-3-quinuclidinol, however, adopts a centrosymmetric point group 2/m(C2h), undergoing a nonferroelectric high-temperature phase transition. This finding reveals the enormous benefits of homochirality in designing high-Tcferroelectrics, and sheds light on exploring homochiral ferroelectrics with great application.

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Wu, Ming, Yanan Xiao, Yu Yan, Yongbin Liu, Huaqiang Li, Jinghui Gao, Lisheng Zhong i Xiaojie Lou. "Achieving Good Temperature Stability of Dielectric Constant by Constructing Composition Gradient in (Pb1−x,Lax)(Zr0.65,Ti0.35)O3 Multilayer Thin Films". Materials 15, nr 12 (10.06.2022): 4123. http://dx.doi.org/10.3390/ma15124123.

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Ferroelectrics with a high dielectric constant are ideal materials for the fabrication of miniaturized and integrated electronic devices. However, the dielectric constant of ferroelectrics varies significantly with the change of temperature, which is detrimental to the working stability of electronic devices. This work demonstrates a new strategy to design a ferroelectric dielectric with a high temperature stability, that is, the design of a multilayer relaxor ferroelectric thin film with a composition gradient. As a result, the fabricated up-graded (Pb,La)(Zr0.65,Ti0.35)O3 multilayer thin film showed a superior temperature stability of the dielectric constant, with variation less than 7% in the temperature range from 30 °C to 200 °C, and more importantly, the variation was less than 2.5% in the temperature range from 75 °C to 200 °C. This work not only develops a dielectric material with superior temperature stability, but also demonstrates a promising method to enhance the temperature stability of ferroelectrics.

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Benedek, Nicole A., i Michael A. Hayward. "Hybrid Improper Ferroelectricity: A Theoretical, Computational, and Synthetic Perspective". Annual Review of Materials Research 52, nr 1 (1.07.2022): 331–55. http://dx.doi.org/10.1146/annurev-matsci-080819-010313.

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We review the theoretical, computational, and synthetic literature on hybrid improper ferroelectricity in layered perovskite oxides. Different ferroelectric mechanisms are described and compared, and their elucidation using theory and first-principles calculations is discussed. We also highlight the connections between crystal chemistry and the physical mechanisms of ferroelectricity. The experimental literature on hybrid improper ferroelectrics is surveyed, with a particular emphasis on cation-ordered double perovskites, Ruddlesden–Popper and Dion–Jacobson phases. We discuss preparative routes for synthesizing hybrid improper ferroelectrics in all three families and the conditions under which different phases can be stabilized. Finally, we survey some synthetic opportunities for expanding the family of hybrid improper ferroelectrics.

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Patrusheva, Tamara, Sergey Petrov, Ludmila Drozdova i Aleksandr Shashurin. "FERROELECTRICS IN ACOUSTOELECTRONICS". VOLUME 39, VOLUME 39 (2021): 217. http://dx.doi.org/10.36336/akustika202139217.

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Аcoustoelectronics is one of the areas of acoustics, associated with the use of mechanical resonance effects and the piezoelectric effect, as well as the effect based on the interaction of electric fields with waves of acoustic stresses in a piezoelectric material. The main materials used in acoustoelectronics are ferroelectrics, which are mainly complex oxide materials. This article discusses the possibility of increasing the purity and homogeneity of ferroelectric materials, as well as softening the regimes of their synthesis using the solution extraction-pyrolytic method. It is shown that the synthesis temperatures of BaTiO3, SrTiO3, and Pb(Zr)TiO3 ferroelectric films are reduced to 550-600°C, and the synthesis time is down to 5-10 minutes. The dielectric constant and Curie temperature values correspond to the maximum characteristics for these materials. Thus, using the extraction-pyrolytic method we obtained suitable for use in acoustoelectronic technology ferroelectric films.

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Dong, Guohua, Suzhi Li, Mouteng Yao, Ziyao Zhou, Yong-Qiang Zhang, Xu Han, Zhenlin Luo i in. "Super-elastic ferroelectric single-crystal membrane with continuous electric dipole rotation". Science 366, nr 6464 (24.10.2019): 475–79. http://dx.doi.org/10.1126/science.aay7221.

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Ferroelectrics are usually inflexible oxides that undergo brittle deformation. We synthesized freestanding single-crystalline ferroelectric barium titanate (BaTiO3) membranes with a damage-free lifting-off process. Our BaTiO3 membranes can undergo a ~180° folding during an in situ bending test, demonstrating a super-elasticity and ultraflexibility. We found that the origin of the super-elasticity was from the dynamic evolution of ferroelectric nanodomains. High stresses modulate the energy landscape markedly and allow the dipoles to rotate continuously between the a and c nanodomains. A continuous transition zone is formed to accommodate the variant strain and avoid high mismatch stress that usually causes fracture. The phenomenon should be possible in other ferroelectrics systems through domain engineering. The ultraflexible epitaxial ferroelectric membranes could enable many applications such as flexible sensors, memories, and electronic skins.

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Zhang, J. P., i J. S. Speck. "Identification of the polarized microregions in PLZT". Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 556–57. http://dx.doi.org/10.1017/s0424820100170517.

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Relaxor ferroe lee tries are classified by broad or diffuse transitions from their high temperature paraelectric (non-polar phase) to their low temperature ferroelectric phase. This is in contrast to conventional ferroelectrics such as PbTiO3 that show discrete ferroelectric transitions characterized by Curie-Weiss behavior in the dielectric susceptibility near the Curie transition temperature Tc. For relaxor ferroelectrics, the transition has a breadth on the order of 100°C The polarized domains normally show complex nanoscale mottled contrast in either bright field or dark field, two-beam or systematic row scattering contrast images; as an example, this contrast is shown in Fig. 1. The nanoscale contrast appears to be intimately associated with the relaxor phase; however, the physical origins of the contrast remain unclear. It is known that in classical treatments of ferroelectrics, the polarization and strain are the primary order parameters for the paralelectric-ferroelectric phase transition. For classical first order ferroelectric transitions, such as in PbTiO3 or BaTiO3, there is a concurrently spontaneous polarization and strain. However, these order parameters need not be directly coupled, and it may be possible that through the relaxor transition, strain and polarization are uncoupled. In this experimental effort we will demonstrate techniques that separate strain contrast from structure factor contrast, the latter being associated with polarization or compositional fluctuations.

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Shao, Yu-Tsun, i Jian-Min Zuo. "Nanoscale symmetry fluctuations in ferroelectric barium titanate, BaTiO3". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 73, nr 4 (19.07.2017): 708–14. http://dx.doi.org/10.1107/s2052520617008496.

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Crystal charge density is a ground-state electronic property. In ferroelectrics, charge is strongly influenced by lattice andvice versa, leading to a range of interesting temperature-dependent physical properties. However, experimental determination of charge in ferroelectrics is challenging because of the formation of ferroelectric domains. Demonstrated here is the scanning convergent-beam electron diffraction (SCBED) technique that can be simultaneously used for imaging ferroelectric domains and identifying crystal symmetry and its fluctuations. Results from SCBED confirm the acentric tetragonal, orthorhombic and rhombohedral symmetry for the ferroelectric phases of BaTiO3. However, the symmetry is not homogeneous; regions of a few tens of nanometres retaining almost perfect symmetry are interspersed in regions of lower symmetry. While the observed highest symmetry is consistent with the displacive model of ferroelectric phase transitions in BaTiO3, the observed nanoscale symmetry fluctuations are consistent with the predictions of the order–disorder phase-transition mechanism.

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Wang, Jian-Jun, Bo Wang i Long-Qing Chen. "Understanding, Predicting, and Designing Ferroelectric Domain Structures and Switching Guided by the Phase-Field Method". Annual Review of Materials Research 49, nr 1 (lipiec 2019): 127–52. http://dx.doi.org/10.1146/annurev-matsci-070218-121843.

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Understanding mesoscale ferroelectric domain structures and their switching behavior under external fields is critical to applications of ferroelectrics. The phase-field method has been established as a powerful tool for probing, predicting, and designing the formation of domain structures under different electromechanical boundary conditions and their switching behavior under electric and/or mechanical stimuli. Here we review the basic framework of the phase-field model of ferroelectrics and its applications to simulating domain formation in bulk crystals, thin films, superlattices, and nanostructured ferroelectrics and to understanding macroscopic and local domain switching under electrical and/or mechanical fields. We discuss the possibility of utilizing the structure-property relationship learned from phase-field simulations to design high-performance relaxor piezoelectrics and electrically tunable thermal conductivity. The review ends with a summary of and an outlook on the potential new applications of the phase-field method of ferroelectrics.

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Kho, Wonwoo, Hyunjoo Hwang, Jisoo Kim, Gyuil Park i Seung-Eon Ahn. "Improvement of Resistance Change Memory Characteristics in Ferroelectric and Antiferroelectric (like) Parallel Structures". Nanomaterials 13, nr 3 (21.01.2023): 439. http://dx.doi.org/10.3390/nano13030439.

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Recently, considerable attention has been paid to the development of advanced technologies such as artificial intelligence (AI) and big data, and high-density, high-speed storage devices are being extensively studied to realize the technology. Ferroelectrics are promising non-volatile memory materials because of their ability to maintain polarization, even when an external electric field is removed. Recently, it has been reported that HfO2 thin films compatible with complementary metal–oxide–semiconductor (CMOS) processes exhibit ferroelectricity even at a thickness of less than 10 nm. Among the ferroelectric-based memories, ferroelectric tunnel junctions are attracting attention as ideal devices for improving integration and miniaturization due to the advantages of a simple metal–ferroelectric–metal two-terminal structure and low ultra-low power driving through tunneling. The FTJs are driven by adjusting the tunneling electrical resistance through partial polarization switching. Theoretically and experimentally, a large memory window in a broad coercive field and/or read voltage is required to induce sophisticated partial-polarization switching. Notably, antiferroelectrics (like) have different switching properties than ferroelectrics, which are generally applied to ferroelectric tunnel junctions. The memory features of ferroelectric tunnel junctions are expected to be improved through a broad coercive field when the switching characteristics of the ferroelectric and antiferroelectric (like) are utilized concurrently. In this study, the implementation of multiresistance states was improved by driving the ferroelectric and antiferroelectric (like) devices in parallel. Additionally, by modulating the area ratio of ferroelectric and antiferroelectric (like), the memory window size was increased, and controllability was enhanced by increasing the switchable voltage region. In conclusion, we suggest that ferroelectric and antiferroelectric (like) parallel structures may overcome the limitations of the multiresistance state implementation of existing ferroelectrics.

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Li, Yibao, Ye Du, Chao-Ran Huang, Hang Peng, Yu-Ling Zeng, Jun-Chao Liu i Wei-Qiang Liao. "Homochiral anionic modification toward the chemical design of organic enantiomeric ferroelectrics". Chemical Communications 57, nr 42 (2021): 5171–74. http://dx.doi.org/10.1039/d1cc01675j.

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Lai, Keji. "Spontaneous polarization in van der Waals materials: Two-dimensional ferroelectrics and device applications". Journal of Applied Physics 132, nr 12 (28.09.2022): 121102. http://dx.doi.org/10.1063/5.0116445.

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The research on two-dimensional (2D) van der Waals ferroelectrics has grown substantially in the last decade. These layered materials differ from conventional thin-film oxide ferroelectrics in that the surface and interface are free from dangling bonds. Some may also possess uncommon properties, such as bandgap tunability, mechanical flexibility, and high carrier mobility, which are desirable for applications in nanoelectronics and optoelectronics. This Tutorial starts by reviewing the theoretical tools in 2D ferroelectric studies, followed by discussing the material synthesis and sample characterization. Several prototypical electronic devices with innovative functionalities will be highlighted. Readers can use this article to obtain a basic understanding of the current status, challenges, and future prospects of 2D ferroelectric materials.

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Matsuo, Hiroki, i Yuji Noguchi. "Bulk photovoltaic effect in ferroelectrics". Japanese Journal of Applied Physics 63, nr 6 (3.06.2024): 060101. http://dx.doi.org/10.35848/1347-4065/ad442e.

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Abstract The bulk photovoltaic (PV) effect in ferroelectric materials has attracted worldwide attention for novel optoelectronic applications utilizing above-bandgap photovoltages, light-polarization-dependent photocurrents, photocurrent generation by terahertz light, etc. One of the drawbacks is its weak photoresponse under visible-light irradiation, and thereby the development of visible-light-active ferroelectrics has been an important issue. In this review, firstly, we introduce the history, mechanisms, and physical features of the bulk PV effect. Secondly, we summarize the properties of representative ferroelectric oxides and two-dimensional nanomaterials. Moreover, we describe a material design for enhancing the visible-light photoresponse based on bandgap tuning and gap-state engineering. Finally, we discuss future prospects of ferroelectric PV devices with a high conversion efficiency.

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Celano, Umberto, Mihaela Popovici, Karine Florent, Simone Lavizzari, Paola Favia, Kris Paulussen, Hugo Bender, Luca di Piazza, Jan Van Houdt i Wilfried Vandervorst. "The flexoelectric effect in Al-doped hafnium oxide". Nanoscale 10, nr 18 (2018): 8471–76. http://dx.doi.org/10.1039/c8nr00618k.

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After the observation of ferroelectric HfO₂, interest in ferroelectric-based nanoelectronics has been renewed. However, ferroelectrics also show coupling between the electrical polarization and the deformation gradient, defined as flexoelectricity. Here we show the flexoelectric effect in Al-doped hafnium oxide.

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Paramonova, Ekaterina, Vladimir Bystrov, Xiangjian Meng, Hong Shen, Jianlu Wang i Vladimir Fridkin. "Polarization Switching in 2D Nanoscale Ferroelectrics: Computer Simulation and Experimental Data Analysis". Nanomaterials 10, nr 9 (15.09.2020): 1841. http://dx.doi.org/10.3390/nano10091841.

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The polarization switching kinetics of nanosized ferroelectric crystals and the transition between homogeneous and domain switching in nanoscale ferroelectric films are considered. Homogeneous switching according to the Ginzburg-Landau-Devonshire (LGD) theory is possible only in two-dimensional (2D) ferroelectrics. The main condition for the applicability of the LGD theory in such systems is its homogeneity along the polarization switching direction. A review is given of the experimental results for two-dimensional (2D) films of a ferroelectric polymer, nanosized barium titanate nanofilms, and hafnium oxide-based films. For ultrathin 2D ferroelectric polymer films, the results are confirmed by first-principle calculations. Fitting of the transition region from homogeneous to domain switching by sigmoidal Boltzmann functions was carried out. Boltzmann function fitting data enabled us to correctly estimate the region sizes of the homogeneous switching in which the LGD theory is valid. These sizes contain several lattice constants or monolayers of a nanosized ferroelectrics.

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35

Maslovskaya, Anna, Tatyana Barabash i Elena Veselova. "Polarization Switching Response and Domain Structure Dynamics Induced in Ferroelectrics by Incident Electron Beams". Solid State Phenomena 247 (marzec 2016): 131–37. http://dx.doi.org/10.4028/www.scientific.net/ssp.247.131.

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The article is devoted to the analysis of polarization reversal process arising in ferroelectrics under electron beam exposure. The advanced model was proposed to describe the polarization switching process in ferroelectrics as well as formation of polarization switching response in electron beam-induced polarization current mode of SEM taking into account the specific character of domain structure dynamics. Simulation of polarization switching current in TGS ferroelectric crystals was performed to estimate the main characteristics of electron beam-induced polarization reversal processes.

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Hoffmann, Michael, Prasanna Venkatesan Ravindran i Asif Islam Khan. "Why Do Ferroelectrics Exhibit Negative Capacitance?" Materials 12, nr 22 (13.11.2019): 3743. http://dx.doi.org/10.3390/ma12223743.

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The Landau theory of phase transitions predicts the presence of a negative capacitance in ferroelectric materials based on a mean-field approach. While recent experimental results confirm this prediction, the microscopic origin of negative capacitance in ferroelectrics is often debated. This study provides a simple, physical explanation of the negative capacitance phenomenon—i.e., ‘S’-shaped polarization vs. electric field curve—without having to invoke the Landau phenomenology. The discussion is inspired by pedagogical models of ferroelectricity as often presented in classic text-books such as the Feynman lectures on Physics and the Introduction of Solid State Physics by Charles Kittel, which are routinely used to describe the quintessential ferroelectric phenomena such as the Curie-Weiss law and the emergence of spontaneous polarization below the Curie temperature. The model presented herein is overly simplified and ignores many of the complex interactions in real ferroelectrics; however, this model reveals an important insight: The polarization catastrophe phenomenon that is required to describe the onset of ferroelectricity naturally leads to the thermodynamic instability that is negative capacitance. Considering the interaction of electric dipoles and saturation of the dipole moments at large local electric fields we derive the full ‘S’-curve relating the ferroelectric polarization and the electric field, in qualitative agreement with Landau theory.

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Upadhyay, Trilok Chandra, i Ashish Nautiyal. "Theoretical Study of Ferroelectric Triglycine Sulphate (TGS) Crystal in External Electric Fields". International Letters of Chemistry, Physics and Astronomy 11 (wrzesień 2013): 54–65. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.11.54.

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A modified two sub-lattice pseudospin-lattice coupled mode model of Mitsui et al [Phys. Rev., 111 (1958) 1259] by adding third, fourth order phonon anharmonic interaction and external electric field terms has been applied to ferroelectric triglycine sulphate crystal. Electric field dependence of ferroelectric, dielectric and acoustical properties has been studied. With the help of double time temperature dependent Green’s function method, expressions for shift, width, soft mode frequency, dielectric constant, loss tangent and acoustic attenuation have been derived. Numerically calculations have been made and results have been compared with experimental data reported by Bye et al [Ferroelectrics 4 (1974) 243] and Shreekumar et al [Ferroelectrics 160 (1994) 23] for TGS crystal and a good agreement has been observed.

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Upadhyay, Trilok Chandra, i Ashish Nautiyal. "Theoretical Study of Ferroelectric Triglycine Sulphate (TGS) Crystal in External Electric Fields". International Letters of Chemistry, Physics and Astronomy 11 (2.04.2013): 54–65. http://dx.doi.org/10.56431/p-y0896q.

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A modified two sub-lattice pseudospin-lattice coupled mode model of Mitsui et al [Phys. Rev., 111 (1958) 1259] by adding third, fourth order phonon anharmonic interaction and external electric field terms has been applied to ferroelectric triglycine sulphate crystal. Electric field dependence of ferroelectric, dielectric and acoustical properties has been studied. With the help of double time temperature dependent Green’s function method, expressions for shift, width, soft mode frequency, dielectric constant, loss tangent and acoustic attenuation have been derived. Numerically calculations have been made and results have been compared with experimental data reported by Bye et al [Ferroelectrics 4 (1974) 243] and Shreekumar et al [Ferroelectrics 160 (1994) 23] for TGS crystal and a good agreement has been observed.

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39

Watts, Bernard. "Chemical segregation and self polarisation in ferroelectrics". Processing and Application of Ceramics 3, nr 1-2 (2009): 97–101. http://dx.doi.org/10.2298/pac0902097w.

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Chemical partitioning or segregation is commonly encountered in solid-state syntheses. It is driven by compositional, thermal and electric field gradients. These phenomena can be quite extreme in thin films and lead to notable effects on the electrical properties of ferroelectrics. The segregation in ferroelectric thin films will be illustrated and the mechanisms explained in terms of diffusion processes driven by a potential gradient of the oxygen. The hypothesis can also explain self polarisation and imprint in ferroelectric hysteresis. .

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40

Yu, Qisheng, Jiawei Huang, Changming Ke, Zhuang Qian, Liyang Ma i Shi Liu. "Semiconducting nonperovskite ferroelectric oxynitride designed ab initio". Applied Physics Letters 122, nr 14 (3.04.2023): 142902. http://dx.doi.org/10.1063/5.0141987.

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The recent discovery of HfO2-based and nitride-based ferroelectrics that are compatible to the semiconductor manufacturing process has revitalized the field of ferroelectric-based nanoelectronics. Guided by a simple design principle of charge compensation and density functional theory calculations, we discover that HfO2-like mixed-anion materials, TaON and NbON, can crystallize in the polar [Formula: see text] phase with a strong thermodynamic driving force to adopt anion ordering spontaneously. Both oxynitrides possess large remnant polarization, low switching barriers, and unconventional negative piezoelectric effect, making them promising piezoelectrics and ferroelectrics. Distinct from HfO2 that has a wide bandgap, both TaON and NbON can absorb visible light and have high charge carrier mobilities, suitable for ferroelectric photovoltaic and photocatalytic applications. This class of multifunctional nonperovskite oxynitride containing economical and environmentally benign elements offers a platform to design and optimize high-performing ferroelectric semiconductors for integrated systems.

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MOROZ, LUBOV IGOREVNA, i ANNA GENNADIEVNA MASLOVSKAYA. "MATHEMATICAL MODELS OF FERNETOELECTRIC POLARIZATION CHARACTERISTICS DESCRIBED WITHIN THE FRAMEWORK OF THE LANDAU - GINZBURG - DEVONSHIER THEORY". Messenger AmSU, nr 95 (2021): 12–20. http://dx.doi.org/10.22250/jasu.95.2.

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The paper presents the overview and implementation of mathematical models of ferroelectric polarization characteristics within the framework of the Landau - Ginzburg theory. Mathematical models of polarization switching in ferroelectrics are formalized by means of several types of differential problems. Based on difference methods the computational schemes are constructed for various modifications of the Landau - Khalatnikov model. Numerical simulation of the polarization hysteresis in ferroelectrics with the first-order phase transition is performed. The computational results obtained in Matlab are compared with the experimental data.

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42

Heo, Seungyang, Daseob Yoon, Sangbae Yu, Junwoo Son i Hyun Myung Jang. "Non-volatile ferroelectric control of room-temperature electrical transport in perovskite oxide semiconductor La:BaSnO3". Journal of Materials Chemistry C 5, nr 45 (2017): 11763–68. http://dx.doi.org/10.1039/c7tc03730a.

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Complex oxide heterostructures composed of oxide semiconductor thin films and ferroelectric single crystals have attracted substantial interest due to the electrically switchable channel resistance by the polarization reversal of ferroelectrics.

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Walker, Julian, Rany Miranti, Susanne Linn Skjærvø, Tadej Rojac, Tor Grande i Mari-Ann Einarsrud. "Super-coercive electric field hysteresis in ferroelectric plastic crystal tetramethylammonium bromotrichloroferrate(iii)". Journal of Materials Chemistry C 8, nr 9 (2020): 3206–16. http://dx.doi.org/10.1039/c9tc06918f.

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Ionic plastic crystals are part of an emerging class of hybrid organic–inorganic ferroelectrics. Their super-coercive electric field hysteresis bares the signatures of ferroelectric switching, including interesting contributions from defects.

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Kim, Younghun, Jungeun Kim, Akihiko Fujiwara, Hiroki Taniguchi, Sungwng Kim, Hiroshi Tanaka, Kunihisa Sugimoto i in. "Hierarchical dielectric orders in layered ferroelectrics Bi2SiO5". IUCrJ 1, nr 3 (30.04.2014): 160–64. http://dx.doi.org/10.1107/s2052252514008008.

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Electric dipole engineering is now an emerging technology for high electron-mobility transistors, ferroelectric random access memory and multiferroic devicesetc. Although various studies to provide insight into dipole moment behaviour, such as phase transition, order and disorder states, have been reported, macroscopic spontaneous polarization has been mainly discussed so far. Here, visualization of the electric dipole arrangement in layered ferroelectrics Bi2SiO5by means of combined analysis of maximum entropy charge density and electrostatic potential distribution analysis based on synchrotron radiation X-ray powder diffraction data is reported. It was found that the hierarchical dipole orders, the weak-ferroelectric and ferroelectric configurations, were observed in the Bi2O2and the SiO3layers, respectively, and the ferrielectric configuration was realised by the interlayer interaction. This discovery provides a new method to visualize the local polarization in ferroelectric materials.

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45

KOO, JE HUAN, GUANGSUP CHO i JONG-JEAN KIM. "EFFECTIVE PHOTON EXCHANGE CORRELATIONS IN FERROELECTRICS". International Journal of Modern Physics B 20, nr 22 (10.09.2006): 3247–55. http://dx.doi.org/10.1142/s0217979206035436.

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We propose a photon correlation theory for ferroelectrics especially focused on KDP-type where we consider a photon field from its constituent electrons and ions. We derive a Curie–Weiss type dielectric susceptibility from the microscopic Hamiltonian and we obtain the ferroelectric transition temperature, Tc. We calculate the free energy by applying the bosonic operator formalism to the Hamiltonian. A linear temperature-dependent specific heat Cv conforming with experimental data for some ferroelectric materials is obtained. We calculate the isotope exponent, α, on Tc. We also derive phonon dispersion relations in the presence of electron-phonon interactions to show soft modes at Tc.

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Takeda, Mitsuo Wada, Akihiko Arikawa, Ryohei Araki, Yosuke Nakata, Fumiaki Miyamaru i Toshihisa Yamaguchi. "Group-Velocity Anomaly Modes in Hybrid Bands of Photonic Crystals Made of Ferroelectrics". Advances in Science and Technology 98 (październik 2016): 109–14. http://dx.doi.org/10.4028/www.scientific.net/ast.98.109.

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In photonic crystals composed of ferroelectrics, the hybrid bands with corresponding to new additional band gaps are expected to appear around the Brillouin zone’s center and boundaries. In this hybrid bands, the group-velocity anomaly modes related to the phonon-polariton branches are expected to be discovered. Propagation characteristics of the group-velocity anomaly modes in the hybrid bands of one-dimensional photonic crystals fabricated by ferroelectric Li2Ge7O15 single crystals are discussed on the basis of finite element method and finite-difference time-domain numerical analyses and experimental results obtained by terahertz time-domain spectroscopy. It is founded that the electric-field intensity of the standing-wave mode at the end point of the dielectric band branch is found to be localized around all of the ferroelectrics plates in the photonic crystal. In contrast, group-velocity anomaly mode in the vicinity of the standing-wave mode is strongly localized around the first ferroelectrics plate on the incident side and decays as it propagates through the following ferroelectrics plates.

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Zhou, Zhangyang, Zhipeng Gao, Zhengwei Xiong, Gaomin Liu, Ting Zheng, Yuanjie Shi, Mingzhu Xiao i in. "Giant power density from BiFeO₃-based ferroelectric ceramics by shock compression". Applied Physics Letters 121, nr 11 (12.09.2022): 113903. http://dx.doi.org/10.1063/5.0102102.

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Ferroelectric pulsed-power sources with rapid response time and high output energy are widely applied in the defense industry and mining areas. As the core materials, ferroelectric materials with large remnant polarization and high electrical breakdown field should generate high power under compression. Currently, lead zirconate titanate 95/5 ferroelectric ceramics dominated in this area. Due to environmental damage and limited output power of lead-based materials, lead-free ferroelectrics are highly desirable. Here, the electrical response of 0.9BiFeO3-0.1BaTiO3 (BFO-BT) ferroelectric ceramics under shock-wave compression was reported, and a record-high power density of 4.21 × 108 W/kg was obtained, which was much higher than any existing lead-based ceramics and other available energy storage materials. By in situ high-pressure neutron diffraction, the mechanism of shock-induced depolarization of the BFO-BT ceramics was attributed to pressure-induced structural transformation, and the excellent performance was further elaborated by analyzing magnetic structure parameters under high pressures. This work provides a high-performance alternative to lead-based ferroelectrics and guidance for the further development of new materials.

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Zhu, Zhongyunshen, Anton E. O. Persson i Lars-Erik Wernersson. "Sensing single domains and individual defects in scaled ferroelectrics". Science Advances 9, nr 5 (3.02.2023). http://dx.doi.org/10.1126/sciadv.ade7098.

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Ultra-scaled ferroelectrics are desirable for high-density nonvolatile memories and neuromorphic computing; however, for advanced applications, single domain dynamics and defect behavior need to be understood at scaled geometries. Here, we demonstrate the integration of a ferroelectric gate stack on a heterostructure tunnel field-effect transistor (TFET) with subthermionic operation. On the basis of the ultrashort effective channel created by the band-to-band tunneling process, the localized potential variations induced by single domains and individual defects are sensed without physical gate-length scaling required for conventional transistors. We electrically measure abrupt threshold voltage shifts and quantify the appearance of new individual defects activated by the ferroelectric switching. Our results show that ferroelectric films can be integrated on heterostructure devices and indicate that the intrinsic electrostatic control within ferroelectric TFETs provides the opportunity for ultrasensitive scale-free detection of single domains and defects in ultra-scaled ferroelectrics. Our approach opens a previously unidentified path for investigating the ultimate scaling limits of ferroelectronics.

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Li, Bowen, Linping Wang, Liang Gao, Tianhua Xu, Dongyang Zhang, Fangzhou Li, Jike Lyu i in. "Elastic relaxor ferroelectric by thiol‐ene click reaction". Angewandte Chemie International Edition, 15.03.2024. http://dx.doi.org/10.1002/anie.202400511.

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As ferroelectrics hold significance and application prospects in wearable devices, the elastification of ferroelectrics becomes more and more important. Nevertheless, achieving elastic ferroelectrics requires stringent synthesis conditions, while the elastification of relaxor ferroelectric materials remains unexplored, presenting an untapped potential for utilization in energy storage and actuation for wearable electronics. The thiol‐ene click reaction offers a mild and rapid reaction platform to prepare functional polymers. Therefore, we employed this approach to obtain an elastic relaxor ferroelectric by crosslinking an intramolecular carbon‐carbon double bonds (CF=CH) polymer matrix with multiple thiol groups via a thiol‐ene click reaction. The resulting elastic relaxor ferroelectric demonstrates pronounced relaxor‐type ferroelectric behaviour. This material exhibits low modulus, excellent resilience and fatigue resistance, maintaining a stable ferroelectric response even under strains of up to 70%. This study introduces a straightforward and efficient approach for the construction of elastic relaxor ferroelectrics, thereby expanding the application possibilities in wearable electronics.

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Li, Bowen, Linping Wang, Liang Gao, Tianhua Xu, Dongyang Zhang, Fangzhou Li, Jike Lyu i in. "Elastic relaxor ferroelectric by thiol‐ene click reaction". Angewandte Chemie, 15.03.2024. http://dx.doi.org/10.1002/ange.202400511.

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As ferroelectrics hold significance and application prospects in wearable devices, the elastification of ferroelectrics becomes more and more important. Nevertheless, achieving elastic ferroelectrics requires stringent synthesis conditions, while the elastification of relaxor ferroelectric materials remains unexplored, presenting an untapped potential for utilization in energy storage and actuation for wearable electronics. The thiol‐ene click reaction offers a mild and rapid reaction platform to prepare functional polymers. Therefore, we employed this approach to obtain an elastic relaxor ferroelectric by crosslinking an intramolecular carbon‐carbon double bonds (CF=CH) polymer matrix with multiple thiol groups via a thiol‐ene click reaction. The resulting elastic relaxor ferroelectric demonstrates pronounced relaxor‐type ferroelectric behaviour. This material exhibits low modulus, excellent resilience and fatigue resistance, maintaining a stable ferroelectric response even under strains of up to 70%. This study introduces a straightforward and efficient approach for the construction of elastic relaxor ferroelectrics, thereby expanding the application possibilities in wearable electronics.

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