Authors:Sushrisangita Sahoo, K. P. Andryushin, P. K. Mahapatra, R. N. P. Choudhary Abstract: Journal of Advanced Dielectrics, Volume 12, Issue 05, October 2022. The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe[math] ions driven by the oxygen vacancy mediated Fe[math]–V[math] –Fe[math] exchange interaction A giant dielectric permittivity in the order of [math]105 was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers. Citation: Journal of Advanced Dielectrics PubDate: 2022-11-08T08:00:00Z DOI: 10.1142/S2010135X22500199 Issue No:Vol. 12, No. 05 (2022)

Authors:Xiaofang Zhang, Xiujuan Lin, Rui Guo, Changhong Yang, Hui Zhao, Mingyu Zhang, Yan Wang, Xin Cheng, Shifeng Huang Abstract: Journal of Advanced Dielectrics, Ahead of Print. To improve the acoustic radiation performance of the spherical transducer, a prestressed layer is formed in the transducer through fiber winding. The influence of the prestressed layer on the transducer is studied from the effects of the radial prestress ([math][math]) and acoustic impedance, respectively. First, a theoretical estimation of [math][math] is established with a thin shell approximation of the prestressed layer. Then, the acoustic impedance is measured to evaluate the efficiency of sound energy transmission within the prestressed layer. Further, the ideal effects of [math][math] on the sound radiation performances of the transducer are analyzed through finite element analysis (FEA). Finally, four spherical transducers are fabricated and tested to investigate their dependence of actual properties on the prestressed layer. The results show that with the growth of [math][math], the acoustic impedance of the prestressed layer grows, mitigating the enormous impedance mismatch between the piezoelectric ceramic and water, while increasing attenuation of the acoustic energy, resulting in a peak value of the maximum transmitting voltage response (TVR[math]) at 1.18 MPa. The maximum drive voltage increases with [math][math], leading to a steady growth of the maximum transmitting sound level (SL[math]), with a noticeable ascend of 3.9 dB at a 3.44 MPa [math][math]. This is a strong credibility that the prestressed layer could improve the sound radiation performance of the spherical transducer. Citation: Journal of Advanced Dielectrics PubDate: 2022-11-24T08:00:00Z DOI: 10.1142/S2010135X22410041

Authors:E. Koroleva, A. Molokov, S. Vakhrushev Abstract: Journal of Advanced Dielectrics, Ahead of Print. One of the key points in the physics of the relaxors is their response to the applied DC field. Many studies of this topic were made, in particular on the influence of the field on the dielectric properties. However, practically, in all the cases, the measurements were performed at a fixed frequency and usually with the change in the temperature at the fixed field strength. In this paper, we report the evolution of the dielectric spectra at low frequencies (0.1 Hz [math] 1 kHz) at fixed temperature 246 K on changing the DC electric field applied in (111) from 1 kV to 7 kV. Cole-Cole function was used to describe the spectra and the field dependences of the mean relaxation time [math], the oscillation strength [math] and the width parameter [math] were determined. The obtained [math]([math]) and [math] [math]([math]) provide evidence of the field-induced transition from the nonpolar glass-like phase to the nonpolar paraelectric phase at around 1.5 kV/cm. In the paraelectric phase, very fast hardening of the spectra was observed with [math] changing from 10 s to about 10[math]s. The performed analysis demonstrated that the earlier reported positive C-V effect is completely determined by the spectra hardening, while [math][math]l does not show any change in the glass-like phase and monotonously decreases with a field increase in the paraelectric state. For complete understanding of the microscopic origin of the observed phenomena, a detailed study on the short- and long-range structures at the same condition is necessary. Citation: Journal of Advanced Dielectrics PubDate: 2022-11-18T08:00:00Z DOI: 10.1142/S2010135X22500217

Authors:Cen Liang, Changyuan Wang, Wenjun Cao, Hanyu Zhao, Feng Li, Chunchang Wang Abstract: Journal of Advanced Dielectrics, Ahead of Print. In this work, (1 [math])(0.92NaNbO3–0.08BaTiO3)–[math]Ca[math]La[math]TiO3 (NNBT – [math]CLT) ceramics were successfully designed and prepared by the solid-state reaction method. Investigations on the structure, dielectric, and energy storage properties were performed. The NNBT – 0.25CLT ceramic with orthorhombic phase at room temperature was found to exhibit extremely small grain size and compacted microstructure. A large [math] of 3.1 J/cm3 and a high [math] of 91.5% under the electric field of 360 kV/cm were achieved simultaneously in the sample. In addition, the energy storage performance of the sample exhibits thermal stability over the temperature range of 25–140[math]C and the frequency range of 5–500 Hz. The charge and discharge tests reveal that the ceramic shows a large current density [math] of 965 A/cm2 and power density [math] of 154 MW/cm3. This work demonstrates that the NNBT–0.25CLT ceramic is a prospective energy storage material for potential application in the field of pulsed power devices. Citation: Journal of Advanced Dielectrics PubDate: 2022-11-17T08:00:00Z DOI: 10.1142/S2010135X22420048

Authors:Ziyue Ma, Jianye Zhu, Jianhua Wu, Yanhua Hu, Xiaojie Lou, Ningning Sun, Ye Zhao, Yong Li, Xihong Hao Abstract: Journal of Advanced Dielectrics, Ahead of Print. Ferroelectric materials are considered to be the most competitive energy storage materials for applications in pulsed power electronics due to excellent charge–discharge properties. However, the low energy storage density is the primary problem limiting their practical application. In this study, (1[math])Na[math]Bi[math]TiO3–[math]Sr[math]La[math]TiO3[(1[math])NBT–[math]SLT] ferroelectric ceramics are found to exhibit excellent energy storage performances through a synergistic strategy. As the SLT concentration increases, the relaxation characteristic increases significantly and the breakdown strength increases dramatically from 150 kV/cm to 220 kV/cm. The recoverable energy storage density of the 0.55NBT–0.45SLT ceramic is 2.86 J/cm3 with an energy storage efficiency of 88% under an electric field of 220 kV/cm. Furthermore, the ceramic with [math] = 0.45 mol exhibited excellent energy storage stability in the ranges of 20–180[math]C (temperature) and 1–125 Hz (frequency). These excellent properties demonstrate the potential of (1[math])NBT–[math] SLT ceramics when used as dielectric capacitors in pulsed power systems. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-27T07:00:00Z DOI: 10.1142/S2010135X22420036

Authors:Yan Lin, Ru Wang, Jiawei Qu, Shuo Gao, Yi Zhang, Junli Yan, Jigong Hao, Peng Li, Wei Li Abstract: Journal of Advanced Dielectrics, Ahead of Print. Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics, the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring. Herein, the textured (1-[math])(K[math]Na[math])(Nb[math]Sb[math])O3-[math](Bi[math]Na[math])HfO3([math] = 0.01-0.045) lead-free ceramics were synthesized by templated grain-growth method. The high piezoelectric performance (d[math] of 474 pC/N and strain of 0.21%) and excellent temperature stability (unipolar strain maintained within 4.3% change between 30[math]C and 165[math]C) were simultaneously achieved in the textured KNNS-0.03BNH ceramics. The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in textured ceramics. The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration. This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-26T07:00:00Z DOI: 10.1142/S2010135X22440064

Authors:Yunyun Feng, Changhong Yang, Xiaoying Guo, Wei Sun, Wenxuan Wang, Xiujuan Lin, Shifeng Huang Abstract: Journal of Advanced Dielectrics, Ahead of Print. BiScO3–PbTiO3 binary ceramics own both high Curie temperature and prominent piezoelectric properties, while the high dielectric loss needs to be reduced substantially for practical application especially at high temperatures. In this work, a ternary perovskite system of (1–[math]–[math])BiScO3–[math]PbTiO3–[math]Bi(Mn[math]Sb[math])O3 (BS–[math]PT–[math]BMS) with [math]= 0.005, [math]= 0.630–0.645 and [math]= 0.015, [math]= 0.625–0.640 was prepared by the traditional solid-state reaction method. The phase structure, microstructure, dielectric/piezoelectric/ferroelectric properties were studied. Among BS–[math]PT–[math]BMS ceramic series, the BS–0.630PT–0.015BMS at morphotropic phase boundary possesses the reduced dielectric loss factor (tan[math] = 1.20%) and increased mechanical quality factor ([math][math] = 84), and maintains a high Curie temperature ( [math] = 410[math]C) and excellent piezoelectric properties ([math][math]= 330 pC/N) simultaneously. Of particular importance, at elevated temperature of 200[math]C, the value of tan[math] is only increased to 1.59%. All these properties indicate that the BS–0.630PT–0.015BMS ceramic has great potential for application in high-temperature piezoelectric devices. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-26T07:00:00Z DOI: 10.1142/S2010135X22500175

Authors:Suilong Huang, Jianwen Chen, Zhen Su, Xiucai Wang, Wenbo Zhu, Wenjun Chen, Xinmei Yu, Peng Xiao Abstract: Journal of Advanced Dielectrics, Ahead of Print. Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy density. Considering the structural design and electrical properties of ferroelectric capacitor, it is still a challenge to find out the optimal energy storage of ferroelectric ceramics during the phase-transition process of amorphous/nanocrystalline and polycrystalline. In this work, a finite element model suitable for the multiphase ceramic system is constructed based on the phase field breakdown theory. The nonlinear coupling relationship of multiple physical fields between multiphase ceramics was taken into account in this model. The basic structures of multiphase ceramics are generated by using the Voronoi diagram construction method. The specified structure of multiphase ceramics in the phase- transition process of amorphous/nanocrystalline and polycrystalline was further obtained through the grain boundary diffusion equation. The simulation results show that the multiphase ceramics have an optimal energy storage in the process of amorphous polycrystalline transformation, and the energy storage density reaches the maximum when the crystallinity is 13.96% and the volume fraction of grain is 2.08%. It provides a research plan and idea for revealing the correlation between microstructure and breakdown characteristics of multiphase ceramics. This simulation model realizes the nonlinear coupling of the multiphase ceramic mesoscopic structure and the phase field breakdown. It provides a reference scheme for the structural design and performance optimization of ferroelectric ceramics. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-21T07:00:00Z DOI: 10.1142/S2010135X22450011

Authors:Xinran Wang, Huanghui Nie, Yan Yan, Gang Liu Abstract: Journal of Advanced Dielectrics, Ahead of Print. The (1−[math])(0.94Bi[math] Na[math]TiO3–0.06BaTiO 3)–[math]KTaO3 (BNBT–[math]KT) lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique, and the phase structure, surface morphology, electrical properties were all thoroughly examined. Every ceramic has a single perovskite structure and there is no second phase, as shown by the XRD patterns and Raman spectra. Scanning electron microscopy revealed that all samples displayed dense microstructure and cubic grain. In addition, KT encourages grain growth due to the oxygen vacancies induced by doping or volatilization of ions at high temperatures. The [math][math]of the ceramics decreases with increasing doping levels due to oxygen vacancies acting as dipoles upon the addition of KT, and the dielectric loss of all samples is low at ambient temperature. In comparison to the pure BNBT ceramic’s bipolar strain value of 0.12%, the BNBT–2KT ceramic achieved a maximum bipolar strain of [math]0.506% and unipolar strain of [math] 0.430% with the corresponding [math][math]∗up to 538 pm/V under 80 kV/cm field. Performance significantly improved as a result of this. A test of the correlation between temperature and ferroelectric properties shows that the largest strain value of the BNBT–2KT ceramic occurs at ambient temperature and that the phase change from ferroelectric to relaxor is complete. Additionally, it is discovered that the BNBT–3KT ceramic can sustain a stable strain across a broad temperature range, suggesting that it has good temperature stability. The aforementioned findings demonstrate that lead-based ceramics may be replaced with BNBT–[math]KT ceramics. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-21T07:00:00Z DOI: 10.1142/S2010135X2250014X

Authors:Hongbo Liu, Jianguo Chen Abstract: Journal of Advanced Dielectrics, Ahead of Print. In this work, Li2CO3 was added into 0.7BiFeO[math]0.3BaZr[math]Ti[math]O[math]0.01molMnO2 (70BFBTMn) piezoelectric ceramics to reduce their sintering temperatures. 70BFBTMn ceramics were sintered by a conventional solid reaction method, and their structural, dielectric, piezoelectric and ferroelectric properties were studied. These results indicate that 0.5% (mole) Li2CO3 is the optimized content and it can reduce the sintering temperature by 100[math]C, making the possibility of the piezoelectric ceramics cofiring with Ag electrodes at low temperatures to manufacture multilayer piezoelectric actuators. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-19T07:00:00Z DOI: 10.1142/S2010135X2241003X

Authors:Mehak Arora, Shubhpreet Kaur, Sunil Kumar, Parambir Singh Malhi, Mandeep Singh, Anupinder Singh Abstract: Journal of Advanced Dielectrics, Ahead of Print. This work promotes the room temperature energy storage properties of the multiferroics. In this approach, impacts of PrFeO3 doping on PT-based solid solutions (Pb[math][math]Pr[math]Ti[math][math]Fe[math]O3, [math] = 0.21, 0.22, 0.23, 0.24, 0.25 and 0.26) have been explored. X-ray diffraction (XRD) patterns were used to estimate the crystallographic parameters, confirming the single phase tetragonal structure. The ferroelectric Curie temperature ([math][math]) is observed to drop from 410 K to below room temperature as the Pr concentration increases. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The sample [math] = 0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm3 with the efficiency of 40.5%. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample [math] = 0.24 shows the maximum response with the coupling coefficient ([math]) = 15.54 g2/emu2. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-13T07:00:00Z DOI: 10.1142/S2010135X22500126

Authors:M. E. Kutepov, G. Ya. Karapetyan, T. A. Minasyan, V. E. Kaydashev, I. V. Lisnevskaya, K. G. Abdulvakhidov, A. A. Kozmin, E. M. Kaidashev Abstract: Journal of Advanced Dielectrics, Ahead of Print. Epitaxial VO2 films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO2 sensor abruptly drops from 0.7 M[math] to 90 [math] when it is heated above [math]65[math]C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO2. In the proposed devices with external load, a SAW does not propagate via VO2 film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50[math] is induced to the SAW transferred through the coupler due to the phase transition in VO2. The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications. Citation: Journal of Advanced Dielectrics PubDate: 2022-10-11T07:00:00Z DOI: 10.1142/S2010135X22500187

Authors:Limin Hou, Changxiao Li, Xinjian Wang, Xiaozhi Wang, Ting Wang, Yu Huan Abstract: Journal of Advanced Dielectrics, Ahead of Print. With the increasing demand of high-power and pulsed power electronic devices, environmental-friendly potassium sodium niobate ((Na[math]K[math])NbO3, KNN) ceramic-based capacitors have attracted much attention in recent years owning to the boosted energy storage density ([math]). Nevertheless, the dielectric loss also increases as the external electric field increases, which will generate much dissipated energy and raise the temperature of ceramic capacitors. Thus, an effective strategy is proposed to enhance the energy storage efficiency ([math]) via tailoring relaxor behavior and bad gap energy in the ferroelectric 0.9(Na[math]K[math])-NbO3–0.1Bi(Zn[math](Nb[math]Ta[math])[math])O3 ceramics. On the one hand, the more diverse ions in the B-sites owing to introducing the Ta could further disturb the long-range ferroelectric polar order to form the short–range polar nanoregions (PNRs), resulting in the high [math]. On the other hand, the introduction of Ta ions could boost the intrinsic band energy gap and thus improve the [math]. As a result, high [math] of 3.29 J/cm3 and ultrahigh [math] of 90.1% at the high external electric field of 310 kV/cm are achieved in [math] = 0.5 sample. These results reveal that the KNN-based ceramics are promising lead-free candidate for high-power electronic devices. Citation: Journal of Advanced Dielectrics PubDate: 2022-09-28T07:00:00Z DOI: 10.1142/S2010135X22420012

Authors:G. Ya. Karapetyan, M. E. Kutepov, E. M. Kaidashev, A. L. Nikolaev Abstract: Journal of Advanced Dielectrics, Ahead of Print. A method for obtaining a new type of surface acoustic wave (SAW) transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated. A method for calculating such a transducer has been developed, its equivalent circuit has been compiled, taking into account propagation losses, losses in the metal film and the inductance of the connecting wires. When the frequency is doubled, the SAW attenuation per unit length increases. Citation: Journal of Advanced Dielectrics PubDate: 2022-09-26T07:00:00Z DOI: 10.1142/S2010135X22500163

Authors:Yongmei Zhang, Liangliang Liu Abstract: Journal of Advanced Dielectrics, Ahead of Print. To solve the problem of directional arrangement of small template particles, we designed a lamination technique for the preparation of dense ceramics with high texture degree based on the phase-field simulation. Referring to the experimental data, the initial microstructures of the template and matrix layers were constructed. The effect of the average length of template on the coarsening behavior of the template layer was investigated in detail. The results suggested that there was a stable stage in the growth process of template grains, which would be conducive to the densification of textured ceramics. This phenomenon has been confirmed by corresponding experiments. In addition, we demonstrated a critical thickness of matrix layer for the preparation of highly textured ceramics by using the template with various average lengths. The grain size of highly textured ceramics could be controlled by adjusting the template size and thickness of matrix layer. Citation: Journal of Advanced Dielectrics PubDate: 2022-09-14T07:00:00Z DOI: 10.1142/S2010135X22500151

Authors:Andryushin Konstantin, Pavelko Alexey, Sahoo Sushrisangita, Shilkina Lidiya, Nagaenko Alxandr, Andryushina Inna, Moysa Maksim, Reznichenko Larisa Abstract: Journal of Advanced Dielectrics, Ahead of Print. Solid solution samples of the three-component system (1 −[math])Pb(Ti[math]Zr[math])O[math]CdNb2O6 with [math] = 0.0125–0.0500, [math] [math] = 0.0125 were obtained by solid phase synthesis followed by sintering using conventional ceramic technology. The crystal structure, microstructure, electrophysical, and thermophysical properties of these ceramics have been studied. It is shown that all studied solid solutions can be divided into two groups (with [math] = 0.0125 and with [math] 0.0125), characterized by different characteristics of the change in properties with variations in external influences. This is probably due to the transition from a perovskite-type structure with a tetragonal (T) unit cell to inhomogeneous solid solutions consisting of a series of T-phases with similar cell parameters. A conclusion is made about the expediency of using the data obtained in the development of similar materials for devices based on them. Citation: Journal of Advanced Dielectrics PubDate: 2022-09-02T07:00:00Z DOI: 10.1142/S2010135X22440052

Authors:Zhenji Zhou, Weimin Xia, Jing Liu, Na Tian, Caiyin You Abstract: Journal of Advanced Dielectrics, Ahead of Print. Dielectric polymer film capacitors with a high-power density as well as efficient charge and discharge rates have great potential for application to fulfill the miniaturized and lightweight requirements of the electronic and stationary power systems. It was reported that the elastic recovery rate and energy storage density of poly (vinylidene fluoride-chlorotrifluoroethylene) [P(VDF-CTFE)] polymer film can be enhanced through thermostatic uniaxial stretching. But it is unknown about the relationship between the stretching rate and above properties. In this study, we investigated the effect of different stretching rates on the conformation, elastic recovery, dielectric constant, and energy storage density of stretched P(VDF-CTFE) polymer films. It was found that the stretching rate significantly affected the formation of polar [math]-crystal phase, causing different dielectric properties. The degrees of elastic recovery of P(VDF-CTFE) film vary with stretching rates. Among them, the elastic recovery rate of the P(VDF-CTFE) 94/6 film is 46.5% at a stretching rate of 15 mm/min, the dielectric constant is 12.25 at 100 Hz, and the energy density reaches 3.95 J/cm3 with the energy loss of 39% at 200 MV/m field. Citation: Journal of Advanced Dielectrics PubDate: 2022-08-19T07:00:00Z DOI: 10.1142/S2010135X22420024

Authors:Xudong Qi, Kai Li, Lang Bian, Enwei Sun, Limei Zheng, Rui Zhang Abstract: Journal of Advanced Dielectrics, Ahead of Print. Relaxor-based ternary Pb(In[math]Nb[math])O3–Pb(Mg[math]Nb[math])O3–PbTiO3(PIN–PMN–PT) single crystals and ceramics are promising candidates for high-performance electromechanical conversion devices. It is known that the domain structure and dielectric diffusion–relaxation characteristics are crucial to the excellent performances of relaxor ferroelectrics. In this work, we prepared the PIN–PMN–PT ceramics with various PIN/PMN proportions and systematically investigated their domain structure and dielectric diffusion–relaxation properties. The effect of PIN/PMN proportion on the domain size and dielectric diffusion–relaxation characteristics was also studied. The investigations showed that PIN–PMN–PT ceramics presented multi-type domain patterns comprising irregular island domains and regular lamellar domains. Moreover, the dependent relations of PIN/PMN proportions on the dielectric diffusion and domain size indicated that the PIN composition has a stronger lattice distortion than PMN composition; increasing the PIN proportion can enhance the dielectric diffusion and decrease the domain size. Our results could deepen the understanding of structure–property relationships of multicomponent relaxor ferroelectrics and guide the design and exploration of new high-performance ferroelectric materials. Citation: Journal of Advanced Dielectrics PubDate: 2022-08-18T07:00:00Z DOI: 10.1142/S2010135X22410028

Authors:Yingzhuo Lun, Jiaqian Kang, Wenfu Zhu, Jianming Deng, Xingan Jiang, Cheng Zhu, Qi Ren, Xian Zi, Ziyan Gao, Tianlong Xia, Zishuo Yao, Xueyun Wang, Jiawang Hong Abstract: Journal of Advanced Dielectrics, Ahead of Print. Driven by the minimization of total energy, the multi-domain morphology is preferred in as-grown ferroelectrics to reduce the depolarization and strain energy during the paraelectric to ferroelectric phase transition. However, the complicated multi-domain is not desirable for certain high-performance ferroelectric electro-optic devices. In this work, we achieve a reproducible and stable large-area monodomain in as-grown bulk ferroelectric single crystal Sn2P2S6. The monodomain dominates the entire single crystal, which is attributed to the internal charge carriers from the photoexcited disproportionation reaction of Sn ions. The charge carriers effectively screen the depolarization field and therefore decrease the depolarization energy and facilitate the formation of monodomain. This work offers a potential approach for engineering bulk ferroelectrics with a stable monodomain, which is desirable for the high-performance ferroelectric electro-optic devices. Citation: Journal of Advanced Dielectrics PubDate: 2022-08-04T07:00:00Z DOI: 10.1142/S2010135X22430019

Authors:Marina V. Il’ina, Olga I. Soboleva, Nikolay N. Rudyk, Maria R. Polyvianova, Soslan A. Khubezhov, Oleg I. Il’in Abstract: Journal of Advanced Dielectrics, Ahead of Print. Recent studies have shown that nitrogen doping of carbon nanotubes (CNTs) can lead to the formation of piezoelectric properties in them, not characteristic of pure CNTs. In this work, nitrogen-doped CNTs were grown by plasma-enhanced chemical vapor deposition and the effect of the aspect ratio of the nanotube length to its diameter on its piezoelectric coefficient [math] was shown. It was observed that as the aspect ratio of the nanotube increased from 7 to 21, the value of [math] increased linearly from 7.3 to 10.7 pm/V. This dependence is presumably due to an increase in curvature-induced polarization because of an increase in the curvature and the number of bamboo-like “bridges” in the nanotube cavity formed as a result of the incorporation of pyrrole-like nitrogen into the nanotube structure. The obtained results can be used in the development of promising elements of nanopiezotronics (nanogenerators, memory elements, and strain sensors). Citation: Journal of Advanced Dielectrics PubDate: 2022-07-07T07:00:00Z DOI: 10.1142/S2010135X22410016