12,853 results on '"HYSTERESIS loop"'
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2. New insights into interface characterization of ceramic matrix composites: Theory and application of hysteresis loops with Coulomb friction
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Ma, Yong, Niu, Xiaochuan, Guo, Shu, Zhang, Lei, Yan, Jiaxuan, and Chen, Yuli
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- 2025
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3. Frequency switching leads to distinctive fast–slow behaviors in Duffing system
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Zhao, Jiahao, Sun, Hanyu, Zhang, Xiaofang, Han, Xiujing, Han, Meng, and Bi, Qinsheng
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- 2024
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4. Experimental discrimination of domain switching behaviors within interfacial and bulk layers in the LiNbO3 domain-wall memory.
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Zhang, Wen Di and Jiang, An Quan
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RATE of nucleation , *DISCONTINUOUS precipitation , *FERROELECTRIC devices , *HYSTERESIS loop , *ELECTRIC fields - Abstract
Multilevel resistance states with respect to the volume of the reversed domains in ferroelectric tunneling junctions and erasable conducting domain walls in an insulating ferroelectric matrix enable high-speed and energy-efficient ferroelectric synapses, memories, and transistors. According to the domain nucleation model, the operation speeds of these devices are assumedly limited by domain nucleation time while the subsequent domain growth time is neglected. Unfortunately, these two times cannot be separated from the experiment yet. Here, we observed independent switching behaviors of domain nucleation and growth at two discrete coercive fields for a mesa-like memory cell formed at the surface of a LiNbO3 single crystal. After the application of an in-plane electric field to two side electrodes, we observed the on currents upon antiparallel domain reversals via the creation of conducting domain walls between them. Once the applied electric field is removed, the domains within the interfacial layers between the two side electrodes and the cell are volatile and switch back into their initial orientations automatically, unlike the nonvolatile bulk domain encoding digital information. In consideration of volatile and nonvolatile natures of the two domains, we separately observed their switching behaviors from the measurements of frequency-dependent domain switching hysteresis loops after programing various write and read pulses. It is found that all coercive fields with the involvement of domain nucleation at the interfaces are always frequency-dependent, unlike domain forward growth within the bulk layer that is frequency-independent. This provides the direct evidence that the operation speed of the low-dimensional ferroelectric device is limited by the domain nucleation rate at the interface. [ABSTRACT FROM AUTHOR]
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- 2025
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5. Quantifying inhomogeneous magnetic fields at the micrometer scale using graphene Hall-effect sensors.
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Petit, Lionel, Blon, Thomas, and Lassagne, Benjamin
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QUANTUM wells , *POSITION sensors , *MAGNETIZATION reversal , *HYSTERESIS loop , *MAGNETIC fields , *SUPERCONDUCTING quantum interference devices - Abstract
The response of a graphene Hall-effect sensor to the inhomogeneous magnetic field generated by a dipole located above it is investigated numerically at room temperature as a function of the dipole position and orientation and as a function of the sensor conduction regime, i.e., diffusive or ballistic. By means of dedicated models, we highlight that the correction factor α frequently used to relate the Hall voltage to the magnetic field averaged over the sensor area can be greatly improved in the high proximity situation enabled by the use of graphene, particularly in the ballistic regime. In addition, it is demonstrated that by fine-tuning the dipole position in the sensor plane, the Hall response becomes highly selective with respect to the dipole orientation. These analyses show that diffusive graphene Hall sensors may be preferred for particle detection, while ballistic ones used as close as possible to a nanomagnet would be preferred for magnetometry. Then, with the help of micromagnetic simulations, the principle of measuring the magnetic hysteresis loop of an isolated nanomagnet with a ballistic Hall sensor is investigated. A large signal-to-noise ratio is demonstrated, which allows for effective probing of magnetization reversal. This shows that devices based on specially designed ballistic graphene Hall crosses promise to outperform state-of-the-art ballistic Hall sensors based on semiconductor quantum wells or micro-SQUID, especially for nano-magnetometry. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Resistive switching behavior of quasi-2D CsPbBr3 memristors: Impact of ambient atmosphere on logic storage and computing integration with anti-crosstalk and reconfiguration features.
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Zhu, Mufan, Yao, ChuTing, Zhang, Xiaofei, He, Song, Cheng, Baochang, and Zhao, Jie
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SURFACE defects , *HYSTERESIS loop , *COPPER , *MEMRISTORS , *ION traps - Abstract
Passive units integrating storage and computing with anti-crosstalk and multi-logic reconstruction are crucial for high computing power and high-density non-volatile storage. In this study, we report an anti-crosstalk and reconfigurable logic memory based on a single passive quasi-two-dimensional (2D) CsPbBr3 device. The effect of the ambient atmosphere (air and N2 environments) on the resistive behavior of the memristors is explored. In air, these devices exhibit negative differential resistance (NDR) effects and antipolar resistive switching behavior, while in N2, they display irreversible switching from low-resistance state to high-resistance state. Various active electrodes (Ag, Cu, Au, and C) were employed to investigate this phenomenon. It is proposed that in air, O ions interact with surface defects under high alternating voltage, retaining a significant quantity of Br− ions within the quasi-2D CsPbBr3, resulting in capacitive-like behavior. Conversely, in N2, surface defects capture Br− ions, leading to the absence of a hysteresis loop in the I-V characteristic. Under N2 operation, write-once-read-many (WORM) capability is achieved. Surprisingly, operating under air enables integrated non-volatile storage and computing, facilitating 12 reconfigurable logic operations in a passive 1R structure and suppressing sneak current in crosstalk setups. This study emphasizes the pivotal role of air in the resistive switching mechanism and provides novel insights for developing next-generation memories tailored for high-density integrated circuits and storage-computing integration. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Iron wool as a heating agent for magnetic catalysis: Experiments and analysis of heating properties under a high-frequency magnetic field.
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Daccache, S., Ghosh, S., Marias, F., Chaudret, B., and Carrey, J.
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EDDY current losses , *HETEROGENEOUS catalysis , *MAGNETIC materials , *HYSTERESIS loop , *MAGNETIC fields , *WOOL - Abstract
Magnetically induced heterogeneous catalysis has been attracting attention due to its high energy efficiency and flexibility for dynamic reactor control. Iron wool is a commercial, low-cost, and versatile heating agent, which has been used in several magnetic catalysis studies, but its heating properties have never been investigated. Here, the properties of three types of Fe wool were studied using optical and electronic microscopy, x-ray diffraction, and measurements of both heating power and high-frequency hysteresis loops. The effects of strand width, packing, and magnetic field amplitude and frequency were studied. A maximum specific absorption rate (SAR) around 700 W/g under a rms field of 47.4 mT at 93 kHz was measured for the larger width Fe wool. High-frequency hysteresis loops were used to quantify the contribution of hysteresis losses and eddy currents to total heating. Eddy currents contribute 65%–90% to the global heating depending on the strand width. Coating the wool with SiO2 and Ni has negative effects on the SAR but none on hysteresis losses. It is interpreted as originating from the cut-off of inter-wire eddy currents due to the insulating (SiO2, oxidized Ni) nature of the coating. Last, it was found that adding more Fe wool in a given volume mostly decreases the SAR. This effect could be not only due to the absorption and/or screening of the field by surface strands but also due to magnetic interactions. The results described in this work give insights into the magnetic heating of microscale magnetic materials and optimize their use for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Growth and ferroelectric properties of Al substituted BiFeO3 epitaxial thin films.
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Joshi, Chhatra R., Acharya, Mahendra, Mankey, Gary J., and Gupta, Arunava
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PIEZORESPONSE force microscopy , *PULSED laser deposition , *FERROELECTRIC materials , *THIN films , *MAGNETIC properties , *HYSTERESIS loop - Abstract
Epitaxial films of BiAl x Fe 1 − x O 3 (xBAFO) were grown on SrTiO 3 (STO) and SrRuO 3 buffered STO substrates using pulsed laser deposition. To understand the effects of Al substitution at the Fe-site of BFO, we systematically investigated its impact on the material's crystal structure, surface morphology, ferroelectric properties, and magnetic properties. Our x-ray diffraction analysis revealed that phase-pure xBAFO films can be stabilized for Al concentrations between 0% and 35%, without the formation of secondary phases, due to the isotypic crystal structures of BiAlO 3 and BiFeO 3. This allowed the rhombohedral structure of BAFO to be preserved. We then characterized the ferroelectric properties of xBAFO (0 ≤ x ≤ 0.25) by analyzing polarization-voltage hysteresis loops, which exhibited a transition from a nearly square shape to a more slanted shape with increasing Al substitution. Additionally, piezoresponse force microscopy revealed that the domain growth mode, shape, size, dimension, and nucleation play a crucial role in the switching behavior of ferroelectric materials. Furthermore, we observed a modest enhancement in magnetization due to the modified spin ordering of Fe atoms with Al substitution. Notably, the optimal ferroelectric and magnetic properties were achieved at an Al concentration of 15%. These findings suggest that BAFO is a promising magnetoelectric material with desired functionalities for realizing BFO-based next-generation non-volatile memory devices. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Morphology and magnetic properties of rapidly quenched Fe-B alloys
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Konstantinidis, Nikolaos, Fos, Alen, Svec, Peter, Papadopoulos, N., Vourna, P., and Hristoforou, Evangelos
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- 2022
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10. Structural and magnetic properties of Ni substituted FeCo alloy obtained through polyol process
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Rajeevan, Vismaya and Justin Joseyphus, R.
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- 2022
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11. Ferroelectric proximity effects in two-dimensional FeSeTe.
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Disiena, Matthew N., Pandey, Nilesh, Luth, Christopher, Sloan, Luke, Shattuck, Reid, Singh, Jatin V., and Banerjee, Sanjay K.
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FERROELECTRICITY , *FERROELECTRIC materials , *SUPERCONDUCTING transitions , *PERMITTIVITY , *HYSTERESIS loop - Abstract
Recent studies have shown that proximity effects are able to substantially modulate the superconducting properties of various quasi-two-dimensional layered materials such as FeSe, FeSeTe, NbSe2, and NbS2. Due to their high surface charge concentration and high dielectric constants, ferroelectric materials provide an interesting avenue for inducing proximity effects in layered superconductors. In this study, we explore the interactions between FeSeTe and the two-dimensional ferroelectrics CuInP2S6 and CuInP2Se6. We found that contrary to the normal behavior of FeSeTe, FeSeTe/CuInP2S6, and FeSeTe/CuInP2Se6 heterostructures display a peculiar two-step superconducting transition. Further testing revealed a hysteresis loop in the IV curves of these samples when measured below the critical temperature indicating the presence of disorder and domains within FeSeTe. We conclude that these domains are responsible for the two-step transition in FeSeTe and hypothesize that they are induced by the domain structure of the aforementioned ferroelectric materials. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Enhancing ferroelectric characterization at nanoscale: A comprehensive approach for data processing in spectroscopic piezoresponse force microscopy.
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Valloire, H., Quéméré, P., Vaxelaire, N., Kuentz, H., Le Rhun, G., and Borowik, Ł.
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PIEZORESPONSE force microscopy , *NANOMECHANICS , *ELECTRONIC data processing , *FERROELECTRIC thin films , *POTASSIUM niobate , *MACHINE learning , *HYSTERESIS loop - Abstract
Switching Spectroscopy Piezoresponse Force Microscopy (SSPFM) stands out as a powerful method for probing ferroelectric properties within materials subjected to incremental polarization induced by an external electric field. However, the dense data processing linked to this technique is a critical factor influencing the quality of obtained results. Furthermore, meticulous exploration of various artifacts, such as electrostatics, which may considerably influence the signal, is a key factor in obtaining quantitative results. In this paper, we present a global methodology for SSPFM data processing, accessible in open-source with a user-friendly Python application called PySSPFM. A ferroelectric thin film sample of potassium sodium niobate has been probed to illustrate the different aspects of our methodology. Our approach enables the reconstruction of hysteresis nano-loops by determining the PR as a function of applied electric field. These hysteresis loops are then fitted to extract characteristic parameters that serve as measures of the ferroelectric properties of the sample. Various artifact decorrelation methods are employed to enhance measurement accuracy, and additional material properties can be assessed. Performing this procedure on a grid of points across the surface of the sample enables the creation of spatial maps. Furthermore, different techniques have been proposed to facilitate post-treatment analysis, incorporating algorithms for machine learning (K-means), phase separation, and mapping cross correlation, among others. Additionally, PySSPFM enables a more in-depth investigation of the material by studying the nanomechanical properties during poling, through the measurement of the resonance properties of the cantilever–tip–sample surface system. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Transient simulation of the electrical hysteresis in a metal/polymer/metal nanostructure.
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Hao, Yutong, Lu, Qiuxia, Zhang, Yalin, Zhang, Maomao, Liu, Xiaojing, and An, Zhong
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ELECTRIC transients , *ELECTRON-phonon interactions , *EQUATIONS of motion , *CONDUCTING polymers , *CURRENT-voltage characteristics , *HYSTERESIS loop , *HYSTERESIS - Abstract
The time-dependent quantum transportation through a metal/polymer/metal system is theoretically investigated on the basis of a Su–Schrieffer–Heeger model combined with the hierarchical equations of motion formalism. Using a non-adiabatic dynamical method, the evolution of the electron subspace and lattice atoms with time can be obtained. It is found that the calculated transient currents vary with time and reach stable values after a response time under the bias voltages. However, the stable current as the system reaches its dynamical steady state exhibits a discrepancy between two sweep directions of the bias voltage, which results in pronounced electrical hysteresis loops in the current–voltage curve. By analyzing the evolution of instantaneous energy eigenstates, the occupation number of the instantaneous eigenstates, and the lattice of the polymer, we show that the formation of excitons and the delay of their annihilation are responsible for the hysteretic current–voltage characteristics, where electron–phonon interactions play the key factor. Furthermore, the hysteresis width and amplitude can also be modulated by the strength of the electron–phonon coupling, level-width broadening function, and temperature. We hope these results about past condition-dependent switching performance at a sweep voltage can provide further insight into some of the basic issues of interest in hysteresis processes in conducting polymers. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Mechanical and magnetic properties of TRIP690 steel strengthened by strain-induced martensite
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Peng, Yuqin and Huang, Haihong
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- 2022
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15. Large electrocaloric effect near room temperature induced by domain switching in ferroelectric nanocomposites.
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Yu, Zeqing, Hou, Xu, Zheng, Sizheng, Bin, Chengwen, and Wang, Jie
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PYROELECTRICITY , *FERROELECTRIC polymers , *MORPHOTROPIC phase boundaries , *FERROELECTRIC materials , *NANOCOMPOSITE materials , *HYSTERESIS loop - Abstract
The solid-state refrigeration technique based on the electrocaloric effect (ECE) of ferroelectric materials has been regarded as a promising alternative to vapor compression systems due to its advantages of high efficiency and easy miniaturization. However, the small adiabatic temperature change (ATC) and narrow operating temperature range of ferroelectric materials are key obstacles for their practical applications of ECE refrigeration. To improve the ECE performance of ferroelectric polymer poly(vinylidene fluoride) [P(VDF-TrFE)], PbZr1−xTixO3 (PZT) nanoparticles with larger polarization is herein introduced to form ferroelectric nanocomposites. The phase-field simulation is employed to investigate the dynamic hysteresis loops and corresponding domain evolution of the ferroelectric nanocomposites. The temperature-dependent ATC values are calculated using the indirect method based on the Maxwell relation. The appearance of the double hysteresis loop is observed in P(VDF-TrFE) nanocomposite filled with PbZr0.1Ti0.9O3 nanoparticles [P(VDF-TrFE)–PZT0.9], which is mainly caused by a microscopic domain transition from single domain to polar vortex. Compared to the P(VDF-TrFE), enhanced ATC values associated with the domain transition are unveiled in P(VDF-TrFE)–PZT0.9, and the temperature range of excellent ECE is also effectively broadened. In addition, as the component x of filled PZT nanoparticles increases to cross the morphotropic phase boundary (MPB), the maximum ATC value shows a significant increase. The results presented in this work not only explain the mechanism of domain transition induced excellent ECE in the P(VDF-TrFE)–PZT nanocomposite, but also stimulate future studies on enhancing ECE of P(VDF-TrFE) by introducing ferroelectric nanofillers. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Tuning the out-of-plane magnetic textures of electrodeposited Ni90Fe10 thin films.
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Cotón, N., Andrés, J. P., Jaafar, M., Begué, A., and Ranchal, R.
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MAGNETIC films , *MAGNETIC force microscopy , *THIN films , *HYSTERESIS loop , *MAGNETIC fields - Abstract
This study investigates the out-of-plane magnetization component of electrodeposited Ni90Fe10 thin films grown under different applied magnetic field conditions. The formation of stripe domains is gradual, as there is a thickness range in which the transcritical shape appears in the hysteresis loops, while only magnetic ripples are measured in the magnetic force microscopy images. For instance, samples deposited under the residual magnetic field generated by the switched-off magnetic stirrer exhibit the transcritical shape in the in-plane hysteresis loops at a thickness of 400 nm, even though corresponding magnetic force microscopy images do not reveal the presence of stripe domains. When a perpendicular magnetic field of 100 Oe is applied during growth, stripe domains become visible in microscopy images, along with the transcritical shape in the hysteresis loop at 400 nm. This implies that the critical thickness for stripe formation can be reduced by applying a perpendicular magnetic field during electrodeposition. We have experimentally confirmed that the larger the magnetic field applied in the out-of-plane direction during growth, the smaller the critical thickness. These results underscore the importance of controlling the external magnetic field during electrodeposition for more effective tuning of the magnetic textures in electrodeposited Ni90Fe10 films. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Quasipolaron surface states in antiferromagnetic dielectrics.
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Yu, Yang, Wang, Changyue, Dai, Bo, Chen, Junhao, and Chen, Kai
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SURFACE states , *POLARIZATION (Electricity) , *DIELECTRICS , *HYSTERESIS loop , *COPPER - Abstract
Dynamic responses of copper titanates to alternating electric fields with different strengths are characterized in terms of dielectric spectrums. This work extends the introduction of quasipolaron surface polarization (QSP). A collective of quasipolarons pinned at grain surfaces is involved in the electric polarization, which is confirmed by the quadratic polarization–permittivity relation. Because electric polarization is a macroscopic quantum effect, the QSP is described in terms of the density of states (DOS). As a sign of reverse ferroelectricity, dielectric hysteresis loops of reverse-S shape reveal that the characteristic remnant polarization is proportional to the DOS ratio of quasipolaron surface excited to ground states. Although the DOS of the surface ground state is dependent on the mole ratio of quasipolaron quantity, both the DOS and the energy levels of surface excited states show the intrinsic angular-frequency dependence in a power function manner. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Monte Carlo Simulation of An-Isotropic Ising Model Using Metropolis and Wolff Algorithm
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Iqbal, Basit, Sarkar, Kingshuk, Mishra, Yogendra Kumar, editor, Lingamallu, Giribabu, editor, and Ghosh, Tufan, editor
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- 2025
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19. Polarization mechanism in filled tungsten bronze Ba4Sm2Ti4Nb6O30 with pinched P–E hysteresis loops.
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Song, Jia Wen, Wang, Ying, Wu, Shu Ya, Zhu, Xiao Li, and Chen, Xiang Ming
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HYSTERESIS loop , *TUNGSTEN bronze , *FIRST-order phase transitions , *DIELECTRIC relaxation , *FERROELECTRIC transitions , *BARIUM titanate , *BRONZE - Abstract
Ferroelectric transition and polarization characteristics were explored for filled tungsten bronze Ba4Sm2Ti4Nb6O30 ceramics with pinched P–E hysteresis loops. Two dielectric permittivity peaks were observed at around 553 and 486 K on heating and cooling cycles, respectively, with a large thermal hysteresis (∼77 K), indicating the first-order ferroelectric phase transition behavior in the present ceramics. In addition, a low-temperature dielectric relaxation appeared at around 300 K, following the Vogel–Fulcher relationship, which is related to thermal activation related to the polarization in the ab plane. Pinched P–E hysteresis loops were detected in the temperature range of 293–453 K with two pairs of coercive fields, indicating certain polar reversal mechanism, while E1 corresponds to the reversal field needed for all the ferroelectric domains in the system, and E2 is the back switch field from the polar state to the nonpolar state. Therefore, (E1–E2)/2 is the effect coercive field for the polar domain induced by the field transition. Temperature dependence of the coercive fields E1, E2, and (E1–E2)/2 is fitted to the Vopsaroiu model with different activated energies obtained for different temperature ranges, based on which the polarization dynamics of the pinched hysteresis loops are discussed. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Magnetization dynamics and spin-glass-like origins of exchange-bias in Fe–B–Nb thin films.
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Masood, Ansar, Belova, L., and Ström, V.
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THIN films , *EXCHANGE bias , *AMORPHOUS alloys , *REMANENCE , *LOW temperatures , *HIGH temperatures , *METALLIC glasses , *HYSTERESIS loop - Abstract
The phenomenon of exchange bias has been extensively studied within crystalline materials, encompassing a broad spectrum from nanoparticles to thin-film systems. Nonetheless, exchange bias in amorphous alloys has remained a relatively unexplored domain, primarily owing to their inherently uniform disordered atomic structure and lacking grain boundaries. In this study, we present a unique instance of exchange bias observed in Fe–B–Nb amorphous thin films, offering insights into its origins intertwined with the system's spin-glass-like behavior at lower temperatures. The quantification of exchange bias was accomplished through a meticulous analysis of magnetic reversal behaviors in the liquid-helium temperature range, employing a zero-field cooling approach from various initial remanent magnetization states (±MR). At reduced temperatures, the appearance of asymmetric hysteresis, a hallmark of negative exchange bias, undergoes a transformation into symmetric hysteresis loops at elevated temperatures, underscoring the intimate connection between exchange-bias and dynamic magnetic states. Further investigations into the magnetic thermal evolution under varying probe fields reveal the system's transition into a spin-glass-like state at low temperatures. We attribute the origin of this unconventional exchange bias to the intricate exchange interactions within the spin-glass-like regions that manifest at the interfaces among highly disordered Fe-nuclei. The formation of Fe-nuclei agglomerates at the sub-nanometer scale is attributed to the alloy's limited glass-forming ability and the nature of the thin-film fabrication process. We propose that this distinctive form of exchange bias represents a novel characteristic of amorphous thin films. [ABSTRACT FROM AUTHOR]
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- 2023
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21. Analyzing the bending deformation of van der Waals-layered materials by a semi-discrete layer model.
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Akiyoshi, Masao, Shimada, Takahiro, and Hirakata, Hiroyuki
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DEFORMATIONS (Mechanics) , *PYROLYTIC graphite , *LOADING & unloading , *FINITE element method , *CANTILEVER bridges , *MECHANICAL models , *COHESIVE strength (Mechanics) , *HYSTERESIS loop - Abstract
Van der Waals (vdW)-layered materials, such as graphite, exhibit unique mechanical properties owing to their structural and mechanical anisotropies. This study reports the development of a mechanical model that reproduces the characteristics of the nonlinear and reversible bending deformation of vdW-layered materials, while taking into account the microscopic mechanism of the discrete interlayer slips. The vdW-layered material was modeled as a stack of interacting discrete deformable layers (semi-discrete layer model), and the interlayer interaction was modeled using a cohesive zone model that reproduced the localized interlayer slip. Using the finite-element method, out-of-plane bending deformation analyses were performed on the cantilevers of the highly oriented pyrolytic graphite (HOPG) and MoTe2, and the validity of the model was verified by comparing it with the experimental results. The model accurately reproduced the loading and unloading behaviors in the experiments for the submicron HOPG cantilevers or the large nonlinear and reversible deformation with a hysteresis loop. Furthermore, the model reproduced well the characteristics of the bending experiments for the micro-MoTe2 cantilevers, or the intermittent decrease in stiffness during the loading process and deformation restoration during the unloading process. These results demonstrated that the designed semi-discrete layer model can be universally applied to reproduce the bending deformation characteristics of a variety of vdW-layered materials and can be employed to effectively elucidate the underlying deformation mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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22. Spin texture and energy analysis in artificial magnetic lattice inspired by nanosphere lithography
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Ravichandran, Sandhya, Sinha, Jaivardhan, Mahadeva, Rajesh, and Ganguly, Arnab
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- 2025
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23. A ferroelectric helical polymer.
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Bandyopadhyay, Supriya, Barman, Shubhankar, Paul, Swadesh, Datta, Anuja, and Ghosh, Suhrit
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HYSTERESIS loop , *FERROELECTRICITY , *CHROMOPHORES , *TEMPERATURE - Abstract
This communication introduces helical polyacetylene (P1) with an appended acceptor (A)–donor (D)–acceptor (A) conjugated chromophore as a promising ferroelectric candidate. The helical conformation of P1 leads to a highly stable chiral assembly of the appended ADA chromophores. This results in prominent ferroelectricity as evident from the superior hysteresis loop at room temperature, exhibiting a saturation polarization (PS) value ∼2 μC cm−2 and remanent polarization (Pr) value ∼1.8 μC cm−2 at a low coercive field (Ec) of 5.2 kV cm−1, rarely reported before for purely organic systems. [ABSTRACT FROM AUTHOR]
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- 2025
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24. Micromorphology tunable Eu2O3 submicron spheres reinforced boron-containing HDPE composites for neutron and gamma-ray complex radiation shielding.
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Huo, Zhipeng, Lu, Yidong, Chen, Zuoyang, Zhang, Jie, Zhang, Hong, and Zhong, Guoqiang
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GAMMA ray sources , *OSTWALD ripening , *CRYSTAL morphology , *GAMMA rays , *HYSTERESIS loop - Abstract
In this research, a series of Eu 2 O 3 /B 4 C/HDPE composites containing micromorphology tunable Eu 2 O 3 submicron spheres as fillers are prepared for shielding neutron and gamma ray. The influence of microstructure of Eu 2 O 3 fillers on thermal stability, mechanical, and radiation shielding properties of composites are studied in detail. The growth process of Eu 2 O 3 precursor (Eu(OH)CO 3) follows the LaMer and Ostwald ripening mechanism. The FESEM reveal that the microstructure of synthesized Eu 2 O 3 is submicron sphere and the particle size decreases with addition of urea content in the reactant solution. HRTEM and SEAD images reveal that the overall crystal morphology of the Eu 2 O 3 fillers is polycrystalline. BET analyses reveal that the hysteresis loops of nitrogen adsorption-desorption isotherms changes from Type H1 to H3 after Eu 2 O 3 fillers are ball-milled, which is attributed to the suppression of nanoparticle agglomeration by ball milling. The FESEM images and EDS mapping of the fracture surfaces of the composites reveal that Eu 2 O 3 fillers are evenly distributed in the HDPE matrix. It is revealed that under the condition that the agglomeration of the nanoparticles is effectively suppressed, the higher BET-specific surface area and smaller size of Eu 2 O 3 fillers are conducive to the various properties of the composites. The superior composite containing Eu 2 O 3 (R = 1:30)/B 4 C/HDPE has a 99.1 % neutron shielding rate with 15 cm thickness under a 252Cf neutron source and a 73.1 % gamma shielding rate with 15 cm thickness under a 137Cs gamma source. [ABSTRACT FROM AUTHOR]
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- 2025
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25. Synergetic enhancement in the piezoelectric coefficient and electromechanical factor in PYN-PMN-PT ceramics via texture engineering.
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Wu, Jie, Li, Chunchun, Sun, Yuan, Yang, Shuai, Wang, Mingwen, Li, Jinglei, and Li, Fei
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PIEZOELECTRIC ceramics , *HYSTERESIS loop , *CERAMICS , *ROTATIONAL motion , *ENGINEERING - Abstract
[001] textured Mn-doped Pb(Yn 1/2 Nb 1/2)O 3 -Pb(Mg 1/3 Nb 2/3)O 3 -PbTiO 3 (PYN-PMN-PT) ceramics were fabricated via the template grain growth (TGG) method using 3 vol% BaTiO 3 (BT) plate-like templates. Benefit to the [001] grain orientation and "4R" domain configuration, Mn-doped PYN-PMN-PT textured ceramics exhibited significantly enhanced piezoelectric and electromechanical properties. In comparison to randomly oriented ceramics, the textured sample exhibited a nearly doubled piezoelectric coefficient d 33 of 607 pC/N (compared to 306 pC/N) and an increased electromechanical coupling factor k p from 0.50 to 0.65. The origin of the improved piezoelectric and electromechanical properties was analyzed based on measurements of hysteresis loops under different frequencies and temperatures. The smaller internal bias field and near-zero values as temperature over T R-T in [001] textured ceramics indicated facilitated polarization rotation and smoothed pinning effect induced by Mn doping. As a consequence, by forming oriented polarization configuration, [001]-textured ceramics become softer, leading to high piezoelectric properties. [ABSTRACT FROM AUTHOR]
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- 2025
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26. A bulk photovoltaic effect in a zero-dimensional room-temperature molecular ferroelectric [C8N2H22]1.5[Bi2I9].
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Zhibo Chen, Tianhong Luo, Jinrong Wen, Zhanqiang Liu, Jingshan Hou, Yongzheng Fang, and Ganghua Zhang
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PHOTOELECTRIC devices , *OPEN-circuit voltage , *SHORT-circuit currents , *HYSTERESIS loop , *FERROELECTRICITY , *PHOTOVOLTAIC effect , *OPTOELECTRONIC devices - Abstract
Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C8N2H22]1.5[Bi2I9] synthesized hydrothermally. [C8N2H22]1.5[Bi2I9] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8N2H22]1.5[Bi2I9] with a spontaneous polarization (Ps) of 1.3 μC cm−2. A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8N2H22]1.5[Bi2I9]-based photoelectric devices with an open-circuit voltage (Voc) of 0.39 V and a short-circuit current density (Jsc) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2. This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
27. Control of structural phase transition and energy storage behavior through cooling rate in (Bi0.5Na0.5)TiO3–BaTiO3 ceramics.
- Author
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Ohshima, Yuri, Ochiai, Yuta, Takagi, Yuka, Nam, Hyunwook, and Nagata, Hajime
- Subjects
- *
PHASE transitions , *HYSTERESIS loop , *ENERGY storage , *ELECTRIC fields , *CERAMICS , *FERROELECTRIC ceramics , *LEAD-free ceramics - Abstract
In lead-free (Bi0.5Na0.5)TiO3–BaTiO3 (BNT–BT) ceramics, the BNT-rich side has R3c ferroelectric domains at room temperature, and modulated P4bm tetragonal nanodomains develop within the R3c rhombohedral phase at approximately the depolarization temperature Td. Such structural phase transitions have conventionally been modulated by doping with additives or by controlling the composition. However, it is considered that the coexistence region between the R3c and P4bm phases is important for enhancing the energy storage behavior because the phase reversal between them, caused by the electric field, can cause the BNT-based ceramics to exhibit an antiferroelectric-like pinched hysteresis loop. In this study, the structural phase transition of BNT–BT ceramics is promoted through process control, that is, by adjusting the cooling rate, and then the stabilization of the P4bm phase and the expansion of the coexistence region of the R3c and P4bm phases were examined, which results in enhanced energy storage behavior. Consequently, BNT–BT ceramics prepared at a slower cooling rate (0.01 °C s−1) than that of normal firing (0.05 °C s−1) demonstrate the stabilization of the P4bm phase and expansion of the coexistence region of the R3c and P4bm phases. Therefore, process control modulates the structural phase transition, which can cause enhanced energy storage behavior. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
28. Visualization of the phonon evolution behavior in NaNbO3 single crystal during field-induced phase transition by in situ Raman spectroscopy.
- Author
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Wang, L. G., Jiang, X. L., Zhu, C. M., Yu, G. B., Su, X. F., Qin, M. Y., Lu, S., Shen, N., and Zheng, X. X.
- Subjects
- *
PHASE transitions , *PULSED power systems , *SINGLE crystals , *RAMAN spectroscopy , *HYSTERESIS loop - Abstract
NaNbO3 (NN) is a significant lead-free alternative for pulse power systems or nonvolatile memories due to its antiferroelectric P phase at room temperature. However, a comparable free energy between P phase and another ferroelectric Q phase leads to an irreversible transition from P to Q phase just under a weak electric field, which results in the unobservable double hysteresis loops. In addition, recent studies reveal that the critical field needed during the transition process is inconsistent between in situ microstructure characterization and macroscopic polarization measurement. Consequently, the intricate field-induced phase transition in NN is perplexing. Based on high sensitivity of Raman spectroscopy to symmetry breaking in lattices, this work systematically investigates the in situ Raman spectra of NN single crystals, analyzing the evolution and depolarization behavior of various phonons under an electric field. Correspondingly, the transition from P to Q phase is determinately identified, accompanied by in-depth understanding of the phonon dynamics of field-induced phase transition. This present work provides a reliable experimental foundation for further probing on the transition mechanism of ferroelectric/antiferroelectric order in dielectrics, as well as facilitating the performance control and application development of NN-based devices. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
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29. A bulk photovoltaic effect in a zero-dimensional room-temperature molecular ferroelectric [C8N2H22]1.5[Bi2I9].
- Author
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Zhibo Chen, Tianhong Luo, Jinrong Wen, Zhanqiang Liu, Jingshan Hou, Yongzheng Fang, and Ganghua Zhang
- Subjects
PHOTOELECTRIC devices ,OPEN-circuit voltage ,SHORT-circuit currents ,HYSTERESIS loop ,FERROELECTRICITY ,PHOTOVOLTAIC effect ,OPTOELECTRONIC devices - Abstract
Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C
8 N2 H22 ]1.5 [Bi2 I9 ] synthesized hydrothermally. [C8 N2 H22 ]1.5 [Bi2 I9 ] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8 N2 H22 ]1.5 [Bi2 I9 ] with a spontaneous polarization (Ps ) of 1.3 μC cm−2 . A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8 N2 H22 ]1.5 [Bi2 I9 ]-based photoelectric devices with an open-circuit voltage (Voc ) of 0.39 V and a short-circuit current density (Jsc ) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2 . This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
30. Evolution of the damage precursor based on the felicity effect in shale.
- Author
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Gautam, PK, Dwivedi, Rishabh, Garg, Peeyush, Majumder, Dipaloke, Agarwal, Siddhartha, McSaveney, Maurice, and Singh, TN
- Subjects
- *
SHALE gas reservoirs , *CYCLIC loads , *HYDRAULIC fracturing , *HYSTERESIS loop , *LOADING & unloading - Abstract
Damage precursors during hydraulic fracturing in shale gas reservoirs may be better understood if the deformation, failure, and acoustic emission (AE) characteristics under cyclic loading are known. Therefore, the purpose of this paper is to investigate the quantitative damage based on the Felicity effect under constant stress lower limit uniaxial cyclic loading-unloading rates (0.5, 1.0, 1.5, 2.0, and 2.5 kN/s). Variations in the b-value and the spatiotemporal evolution of cumulative AE were also used to observe how shale fractures formed. The findings reveal that during the unloading stage, there are many cumulative AE events when the stress level is low (≤1.50 kN/s) but that this number drops significantly when the stress level increases above (>2.0 kN/s). The AE amplitude, AE counts, and cumulative AE energy of each cycle in a loading-unloading test show an increasing trend, but the rate increases in the last cycle. During the whole process of loading and unloading, the Kaiser effects were present in the 3rd cycle at stress levels (≤1.5 kN/s). Still, the Felicity effect appeared in the 2nd and 1st cycles during 2.0 and 2.5 kN/s cyclic loading. The Kaiser effect occurs in the linear elastic stage, while the Felicity effect occurs in the crack initiation and crack damage stage. Furthermore, the Felicity ratio (FR) variations during shale deformation and failure can be divided into four phases: (Phase I = 1.01 ≥ FR > 0.89), (Phase II = 0.89 ≥ FR > 0.48), (Phase III = 0.48 ≥ FR > 0.23), and (Phase IV = FR ≤ 0.23). The b-value is relatively higher under the loading rate below (≤1.50 kN/s), indicating an increase in the number of small AE events. In contrast, the fact that the b-value is relatively smaller under the loading rate above (>2.0 kN/s) indicates that, the number of large AE events increases the number of cracks and fractures. These findings provide important design references for damaged precursors during hydraulic fracturing in shale gas reservoirs. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
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31. Regulation of structure and properties at the ferroelectric–antiferroelectric phase boundary in Ti4+-doped PbZrO3 ceramics.
- Author
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Tu, Fangjian, Li, Bing, Zeng, Mengshi, Huang, Xu, Li, Huiqin, and Liu, Jingsong
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- *
PHASE transitions , *PHYSICAL & theoretical chemistry , *ANTIFERROELECTRIC materials , *INORGANIC chemistry , *HYSTERESIS loop , *FERROELECTRIC ceramics - Abstract
PbZrO3-based antiferroelectric materials are highly advantageous for energy storage applications due to their unique field-induced phase transition from antiferroelectric to ferroelectric states, coupled with excellent energy storage capabilities. However, the transition from antiferroelectric to ferroelectric in PZ-based ceramics remains poorly understood, which limits the further development of this system. Pb0.9325La0.045Zr1−xTixO3 (PLZT) ceramics were synthesized using the solid-state reaction method, focusing on the ferroelectric–antiferroelectric boundary (x = 0.02, 0.04, 0.06, 0.08, 0.1, and 0.12). The effects of varying Ti4+ concentrations on the structural characteristics and performance of the ceramics were examined. X-ray diffraction and Raman spectroscopy analyses revealed that both the unit cell volume and the ZrO6 octahedral lattice distortion of the PLZT ceramics decreased as the Ti content increased, resulting in a weakening of antiferroelectricity and an enhancement of ferroelectricity. The antiferroelectricity disappeared when x = 0.12, and the ceramics transitioned to a ferroelectric state. Under the same calcination and sintering parameters, Ti4+ doping inhibited grain growth, resulting in smaller grain sizes. Domain writing technology and switching spectroscopy piezo-response force microscopy demonstrated that in PLZT ceramics with lower Ti content, the breakdown field strength exceeded the antiferroelectric–ferroelectric phase transition threshold, thereby inhibiting the transition at room temperature and preventing the observation of double hysteresis loops. This study provides significant theoretical and experimental foundations for understanding the structure–property relationships of PLZT materials and underscores the potential application of Ti doping in tuning the properties of antiferroelectric ceramics. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
32. Q-SSC Behavior During Floods in the Isser Watershed, (North-West of Algeria).
- Author
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Baloul, Djouhra, Ghenim, Abderrahmane Nekkache, and Megnounif, Abdesselam
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SUSPENDED sediments , *HYSTERESIS loop , *PRINCIPAL components analysis , *HYSTERESIS , *SEDIMENTS - Abstract
The study aims to establish a graphical relationship between sediment concentration (C) and water discharge (Q) during flood events in the Isser catchment. Hysteresis, indicating a time lag between discharge flow (Q) and suspended sediment concentration (SSC) curves, varies based on sediment availability, event magnitude, and sequence. Based on the 2026 data pairs of water discharge and suspended sediment concentration (Q-SSC), we have selected 22 flood events. The most frequent hysteresis loops were complex (10 loops), with 08 clockwise loops, 02 figure-eight loops, and 02 anti-clockwise loops. Complex hysteresis loops accounted for 63% of solid loads and 37% of water discharge loads, while 50% of total water yield and 23% of total sediment yield were associated with clockwise loops. Principal Component Analysis (PCA) revealed that water discharge load, mean concentration, maximum concentration, and concentration at the flow discharge peak are key variables influencing hysteresis patterns. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
33. In vitro biocompatibility, electrical, mechanical, and structural study of lead-free HAp/BNBK composites for bio-implantation.
- Author
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Swain, Sujata, Kumar, Pawan, Mishra, Balaram, Gupta, Mukesh Kumar, and Sonia
- Subjects
- *
VICKERS hardness , *FRACTURE toughness , *HYSTERESIS loop , *CELL survival , *X-ray diffraction - Abstract
Hydroxyapatite Ca 10 PO 6 (OH) 2 (HAp)/85.4(Bi 0.5 Na 0.5)TiO 3 -2.6(BaTiO 3)-12(Bi 0.5 K 0.5)TiO 3 (BNBK) composites were synthesized by high-energy ball milling-assisted solid-state reaction route. The HAp phase in the HAp/BNBK (HBNBK) composite stabilizes the biocompatible nature, whereas the BNBK phase provides the stress-generated electrical potential for bone regeneration. XRD analysis showed HAp and BNBK phases along with the β-TCP phase as the secondary phase. The influence of surface microstructure, wettability, porosity, and polarization on cell attachment and proliferation was discussed in detail. Mechanical properties such as Vickers hardness, fracture toughness, and brittleness index were studied. Vickers hardness value of 3.23 ± 0.18 GPa and a fracture toughness value of 2.95 ± 0.03 MPa m1/2 were recorded for the 5HBNBK composite samples. Dielectric and P ∼ E hysteresis loop studies revealed the electrical nature of all the composite samples. MG-63 cell lines were used for in vitro study. All the composite samples were hemocompatible in nature and supported cell attachment and viability, as confirmed by MTT and confocal assay. Among all the synthesized composite samples, the 15HBNBK sample was chosen as the optimized one, as more cell viability was recorded for this sample. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
34. Enhanced low-field energy storage performance and dielectric stability in (Bi0.4Sr0.2K0.2Na0.2)(Ti1-xZrx)O3 high-entropy ceramics via B-site modification.
- Author
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Ye, Wenhui, Meng, Dongdong, Hao, Shiji, Liu, Tianyu, Ma, Jinxu, Zhang, Jianjun, and Chen, Kepi
- Subjects
- *
ENERGY storage , *ENERGY density , *PERMITTIVITY , *HYSTERESIS loop , *CELL size , *FERROELECTRIC ceramics - Abstract
The current global energy situation is tense, necessitating the development of high-efficiency, low-cost, and eco-friendly energy materials. In this study, a series of perovskite lead-free relaxor ferroelectric ceramics, denoted as (Bi 0.4 Sr 0.2 K 0.2 Na 0.2)(Ti 1- x Zr x)O 3 (BSKNT- x Zr) were designed to enhance the storage performance. The findings indicate that all samples exhibit a single perovskite structure. As the Zr4+ content increases, the configurational entropy of the samples increases, the cell volume expands, and the hysteresis loops become finer, while maintaining a high maximum polarization (P m) and effectively enhancing the energy storage performance. For the ceramic with x = 0.10, the energy density (W tot), recoverable energy density (W rec), and energy storage efficiency (η) values were determined to be 3.16 J/cm3, 2.67 J/cm3, and 84.3%, respectively, under an electric field of 230 kV/cm. Moreover, the introduction of Zr4+ reduces the relative permittivity and broadens the temperature range (Δ T) that simultaneously satisfies Δ ε/ε 150°C ≤ ±15% and 0 ≤ tan δ ≤ 0.02. This investigation underscores the potential of BSKNT- x Zr ceramics as high-performance, cost-effective, and environmentally friendly energy materials for addressing global energy requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
35. Tunable floating and grounded memristor emulator model.
- Author
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Surendra Prasad, Sagar, Dutta, Somenath, Choubey, Chandan Kumar, Dubey, Sanjay Kumar, Priyadarshini, Bindu, and Ranjan, Rajeev Kumar
- Subjects
- *
CURRENT conveyors , *HYSTERESIS loop , *PASSIVE components , *CAPACITORS , *PROTOTYPES - Abstract
A Differential Difference Current Conveyor Transconductance Amplifier (DDCCTA) based resistor tunable memristor emulator has been proposed in this work. The emulator can be used in both grounded and floating circumstances. The proposed design incorporates only one active block along with few passive components. Moreover, the circuit can operate in both incremental and decremental modes, by simply changing the input ports. The circuit demonstrates all the characteristics of an ideal memristor up to 6 MHz. The proposed model has been simulated using TSMC 0.18 $\mu $ μ m process parameter and occupies an area of 51 × 42.5 $\mu $ μ m2 chip-area, excluding capacitor. The circuit's reliability has been verified by studying non-ideal, non-volatile, Monte-Carlo, process corner variation analysis. The circuit applicability has been tested through series/parallel combinations. To validate the experimental demonstration, AD844AN and CA3080 have been used to make a prototype, which shows good agreement with theoretical and simulation results. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
36. Damage analysis of Functionally Graded Materials under strong cyclic loading.
- Author
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Hamza, Billel, Mokhtari, Mohamed, Slamene, Amir, Medjahed, Rafik, Benzaama, Habib, and Dadoun, Habiba
- Subjects
- *
FUNCTIONALLY gradient materials , *FRACTURE mechanics , *FINITE element method , *HYSTERESIS loop , *SERVICE life , *MATERIAL fatigue - Abstract
Monotonic or cyclic uni-axial loading tests on specimens with or without notch are designed to characterize the materials, and to develop in their results a formulation of the material either analytically or by prediction using a numerical technique, by the finite element method and using the ABAQUS calculation code, The novelty in this work lies in the way the notch itself is subjected to stress. Many studies have focused solely on damage to structures caused by the presence of notches, whereas in reality it's the notches themselves that are subjected to sometimes severe and complex loading, The latter rapidly undermines the service life of these structures, strongly destabilizing the notch to the point of damage by a cyclic and uni-axial loading mode is the embodiment by a numerical prediction of this new idea in this work, which is based beforehand under simple condition on a validation of the numerical model to that of the experimental results, The fatigue behavior of the structure under the equivalent Von Mises flow stress is given by the combined hardening law, and the damage to the structure by crack initiation and propagation is also given by the XFEM (Extend Finite Element Method) technique, in the second part of this work, a reinforcement of the notch in the structure by a locally graded concept with another material surrounding the notch is proposed in order to delay damage under these loading conditions, the results of damage under the effect of the proposed parameters (grading concept and volume fraction index) have been highlighted in this work. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Flux jumps, cluster distribution model and vortex phase diagram of oxygenated YBa2Cu3-xAlxO6+δ single crystals for H|| ab.
- Author
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Babu, Ashna, Sruthy, S. P., and Jaiswal-Nagar, D.
- Subjects
- *
HYSTERESIS loop , *PHOTOELECTRON spectra , *SINGLE crystals , *MAGNETIC fields , *PHASE diagrams - Abstract
This work reports magnetic field direction dependent second magnetisation peak (SMP) anomaly in single crystals of oxygenated for ab. Detailed investigations on crystal A revealed the direction dependence of SMP anomaly at temperatures below 25 K, above which the direction dependence vanishes. The state of spatial order of the vortex lattice was found to be correlated to the vortex lattice symmetry that underwent a change at certain fields and was captured via single flux jumps observed in the third and fifth quadrant of magnetisation hysteresis loops. Bean's critical state profiles drawn to explain the flux jumps required the presence of clusters of in the basal plane of with closely lying binding energies. Large full width at half maximum observed in Cu, O, Y and Ba photoelectron spectra confirmed the validity of the proposed cluster model. A vortex phase diagram incorporating all features in the magnetisation hysteresis loops has been made for oxygenated for || ab depicting various phases. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. High Coercivity and Strong [00l] Crystallographic Texture in Sm(CoFeCuZr)7.4 Nanoflakes Prepared by Surfactant‐Assisted Ball Milling.
- Author
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Raza, Shahzab, Alam, Mehran Khan, Han, Guangbing, and Kang, Shishou
- Subjects
- *
CRYSTAL texture , *MAGNETIZATION reversal , *MAGNETIC domain walls , *HYSTERESIS loop , *REMANENCE - Abstract
Sm(Co0.61Fe0.21Cu0.13Zr0.05)7.4 nanoflakes are prepared by surfactant‐assisted ball milling from annealed ingots, and the ingots are synthesized by the arc‐melting process. The X‐ray diffraction (XRD) patterns of nanoflakes exhibit two hard magnetic phases: Sm2Co17 is the primary hard phase, which provides high saturation magnetization, and SmCo5 acts as a minor hard phase, presumably impeding the movement of magnetic domain walls, thereby increasing intrinsic coercivity. The high coercivity value of 7.2 kOe is achieved after 0.5 h ball milling. In addition, the XRD patterns of nanoflakes at different milling times show a strong [00l] crystallographic texture after the magnetic alignment. A remanence value of 1.03 T and a maximum energy product of 123 kJ m−3 achieve in 0.5 h milled nanoflakes. The aligned nanoflakes show strong anisotropic behavior with a degree of anisotropy value of 0.81. Henkel plots indicate the strong exchange coupling interaction in nanoflakes milled for 0.5 h. Based on the analysis of temperature‐dependent hysteresis loops and initial magnetization curves, the coercivity is controlled by the pinning of domain wall movement and the nucleation of the reverse domains. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. The magnetic characteristics of spinel-type MnCo2O4 at low temperatures.
- Author
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Wang, Wei, Wang, Yongkun, Yan, Yehan, He, Pengzhen, Shezad, Mudssir, Wang, Guanglin, Bao, Lei, and Liu, Houbao
- Subjects
- *
EXCHANGE bias , *SPIN glasses , *HYSTERESIS loop , *LOW temperatures , *CRYSTAL structure - Abstract
We report the magnetic properties of spinel oxide MnCo 2 O 4 at low temperatures which is prepared through the sol-gel reaction process. The XPS results suggest that Mn3+ atoms exist in the octahedral sublattice originally occupied by Co3+ atoms. Afterwards, the AC susceptibility was measured at various frequencies, confirming a spin glass behavior at low temperatures. Additionally, analysis of the hysteresis loops revealed the presence of the exchange bias effect in our sample. The coexistence of spin glass behavior and the exchange bias effect in MnCo 2 O 4 is attributed to the competition between ferromagnetic and antiferromagnetic interaction. The disorders of magnetic atoms in the lattice will also provide synergy for these magnetic behaviors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Ferroelectricity in Ce0.2-HfO2 films around 500 nm in thickness.
- Author
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Wu, Yida, Xu, Junbo, Bai, Mei, Kang, Ruirui, Qiao, Wenjing, Gao, Yangfei, Hu, Yanhua, Wang, Danyang, Zhao, Jiantuo, Wang, Jiping, and Lou, Xiaojie
- Subjects
- *
CHEMICAL solution deposition , *CERIUM oxides , *HAFNIUM oxide , *HYSTERESIS loop , *FERROELECTRICITY , *FERROELECTRIC thin films - Abstract
CeO 2 -HfO 2 solid solution thin films (Hf 1-x Ce x O 2) were deposited on Pt(111)/TiO 2 /SiO 2 /Si(100) substrates using the chemical solution deposition method. This study investigates the influence of CeO 2 content and annealing temperature on the structure and ferroelectric properties of Hf 1-x Ce x O 2 films. Ferroelectric behavior is demonstrated in polycrystalline Hf 0.80 Ce 0.20 O 2 films with thicknesses ranging from 163 to 524 nm. And the structure of the films is analyzed using glancing incidence X-ray diffraction. The comprehensive results indicate that Hf 0.80 Ce 0.20 O 2 films annealed at 850 °C exhibit excellent ferroelectricity. Square hysteresis loops associated with the ferroelectric orthorhombic phase are observed, even in the 524-nm-thick film. The remnant polarization (P r) and coercive field (E c) range from 16 to 18 μC/cm2 and 1100–1250 kV/cm, respectively, under a maximum applied electric field of 2 MV/cm for all Hf 0.80 Ce 0.20 O 2 films. Furthermore, the film presents thickness-insensitive characteristic. The current work paves the new way to design high-performance thick HfO 2 -based ferroelectric films. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Dielectric energy storage properties of low-temperature sintered BNT-based ceramics with LiF and B2O3–Bi2O3 as sintering aids.
- Author
-
Dong, Rizhuang, Shi, Jing, Li, Yujing, Tian, Wenchao, and Liu, Xiao
- Subjects
- *
LEAD-free ceramics , *CERAMIC capacitors , *ENERGY storage , *ENERGY density , *DIELECTRIC loss , *HYSTERESIS loop - Abstract
The dielectric and energy storage properties of (1- x)(0.7(Bi 0.5 Na 0.5)TiO 3 -0.3(Sr 0.7 Bi 0.2)TiO 3)- x Bi(Mg 0.5 Zr 0.5)O 3 (BNT-SBT- x BMZ) ceramics are systematically investigated, and further modified by using the strategy of doping two kinds of sintering aids, LiF and B 2 O 3 –Bi 2 O 3. The results show that all ceramics exhibit a typical perovskite structure. The doping of sintering aids reduces the sintering temperature effectively to below 1000 °C and obtains the dense microstructure. Meanwhile, the ferroelectric long-range order can be disrupted that facilitates the polarization in nano-regions at high temperatures induced by LiF dopants, which enhance the relaxor behavior and form a dielectric platform together with low dielectric loss in a wide temperature range. In addition, extremely slender polarization-electric field (P - E) hysteresis loops are gained by doping LiF in BNT-SBT- x BMZ ceramics associated with an almost non-polar phase that exhibits linear response. In comparison, little change in shape of P - E loops is observed when adding B 2 O 3 –Bi 2 O 3. As a result, outstanding energy storage performances are achieved in sintering-aids modified ceramics under the relatively low electric fields of 180 kV/cm −210 kV/cm. This work provides the optimized energy storage properties and dielectric stability of BNT-based ceramics at reduced sintering temperatures, and pave the way for the cofiring with base metal electrodes in multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. A Current Sensorless Interval Torque Ripple Suppression Method for Permanent Magnet assisted-Switched Reluctance Motor.
- Author
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Chengyi Gong, Junxin Xu, Renquan Xiao, Chaozhi Huang, Xiaobo Liu, and Yong Xiao
- Subjects
TORQUE control ,RELUCTANCE motors ,PERMANENT magnets ,POSITION sensors ,HYSTERESIS loop ,SWITCHED reluctance motors - Abstract
The conventional DITC strategy for switched reluctance motor relies on current for control, while the use of current sensors increases the complexity of the system, and the torque ripple in the two-phase exchange region of the conventional DITC strategy is too large. To solve the above problems, a current sensorless interval torque control (CSITC) method is proposed. Initially, the equivalence between torque and acceleration control is established, replacing the torque loop with an acceleration loop. This forms a dual closedloop system with the speed control loop, enhancing system stability. Subsequently, the variation of the output torque capacity of phase winding of the motor in each conduction region is analyzed, and combined with the inductive characteristics of the motor windings, the two-phase exchange region is divided into two subregions. Different acceleration hysteresis loop control strategies are adopted for the phase windings in each region, so as to realize the stable output of the motor torque. Finally, a three-phase 6/20 permanent magnet assisted-switched reluctance motor (PMa-SRM) is used for simulation and physical verification. The results show that the method can still achieve the steady state of the motor when only the position sensor is used and effectively reduces the torque ripple in the exchange region. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Laboratory evaluation of calcareous sand specimens with inclined sedimentary surfaces.
- Author
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An, Yongning, Liu, Hongjun, Dong, Tong, Liu, Chao, and Zhang, Minsheng
- Subjects
SEDIMENTATION & deposition ,MODULUS of rigidity ,CYCLIC loads ,HYSTERESIS loop ,SHEARING force - Abstract
Sedimentary processes often produce natural and blown calcareous sands that are deposited in inclined and layered formations. These calcareous sands frequently exist in a complex stress state with rotating principal stress axes that result in intricate mechanical properties. To investigate the mechanical behaviors of calcareous sands with inclined sedimentary surfaces, we developed a device to prepare hollow cylindrical specimens from artificially crushed calcareous sands. By combining this device with a hollow cylindrical torsional shear apparatus, undrained monotonic loading and pure principal stress rotation tests were conducted to investigate the static and dynamic properties of the inherently anisotropic calcareous sands. The results indicate that the shear dilatancy property is related to the principal stress direction; the shear dilatancy of calcareous sand decreases as the direction of the principal stress increases, and the peak stress ratio decreases with increasing principal stress direction and increases with increasing deposition direction. In the precyclic loading period, increases in the deposition direction led to increases in the stabilities of the specimens and decreases in excess pore pressure accumulation, which further affect the dynamic shear modulus and damping ratio of the calcareous sand. In the late stage of cyclic loading, the inherent anisotropies of the specimens are destroyed, so that the excess pressure and hysteresis loop characteristics start to converge. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Dynamic hysteresis of an oscillatory contact line.
- Subjects
VIBRATION (Mechanics) ,CONTACT angle ,HYDROPHOBIC surfaces ,MOLECULAR theory ,SILICON surfaces ,HYSTERESIS loop ,SLIDING friction - Abstract
The article "Dynamic hysteresis of an oscillatory contact line" in the Journal of Fluid Mechanics delves into the concept of dynamic hysteresis in oscillatory wetting, revealing a phase delay between contact angle changes and contact line speed. The research demonstrates that dynamic hysteresis can be adjusted by altering surface properties and is connected to static hysteresis. The study suggests new methods for forecasting dynamic hysteresis and stresses the significance of comprehending contact line dynamics in changing conditions. Additionally, the text examines the assessment of contact line friction coefficient in the context of dynamic hysteresis, presenting calculations for mechanical work and highlighting differences in dynamic hysteresis and friction coefficients on various surfaces. The study also addresses the limitations of current models and suggests improvements to enhance predictive accuracy for dynamic wetting behaviors. [Extracted from the article]
- Published
- 2024
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45. Ergodic relaxor state regulated energy storage properties in dielectrics.
- Author
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Lin, Wei, Li, Yang, Zhang, Shumin, He, Yunfei, and Zhao, Shifeng
- Subjects
- *
ENERGY storage , *ORBITAL hybridization , *DIELECTRIC properties , *ENERGY levels (Quantum mechanics) , *CAPACITORS , *HYSTERESIS loop - Abstract
Electrostatic energy storage based on dielectrics is fundamental for high-performance electrical systems. However, developing outstanding energy storage capabilities is challenging because the polarization, loss, and breakdown strength are firmly coupled and mutually restrictive. This work proposes a two-pronged strategy to break out the mutual clamp between these performance parameters by modulating the ergodicity and band structures in Aurivillius ferroelectric films. An inserting layer engineering is carried out using Bi4Ti3O12 as matrix and BiAlO3 as inserting layer. The intrinsic ergodic characteristics drive the realization in the arrangements of internal permanent dipoles through a macroscopically reversible interconversion between relaxor and ferroelectric phases, thereby modulating the pinched double hysteresis loops with both large polarization and low hysteresis. Moreover, the band structure associated with the breakdown strength is additionally regulated by orbital hybridization. Thus, ergodic relaxor ferroelectric film Bi5Ti3AlO15, exhibits an excellent energy storage performance with densities reaching as high as ∼131.8 J cm−3 and efficiencies exceeding 73%. This work overcomes the ubiquitous trade-off among polarization, hysteresis, and breakdown strength, offering extra insight into developing dielectric energy storage capacitors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Electrical Characteristics and Analytical Modeling of GAA-Based Nanowire FeFET.
- Author
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Singh, Mandeep, Chaudhary, Tarun, Wadhwa, Girish, Thakur, Anchal, and Raj, Balwinder
- Subjects
- *
ELECTRIC charge , *POLARIZATION (Electricity) , *FIELD-effect transistors , *ELECTRIC fields , *FERROELECTRIC materials , *HYSTERESIS loop - Abstract
The electrical characteristics of the ferroelectric field-effect transistors (FeFETs) are analyzed numerically and presented in this paper. The metal–ferroelectric–insulator–semiconductor field-effect transistor (MFISFET), among the primary structures, is taken into consideration. The nonsaturated hysteresis loop of the ferroelectric material is described by a novel analytical calculation for the relation of polarization against electric field (
P–E ). The combined impact of the nonuniform concentrations of electric field charge throughout the channel and the nonsaturated polarization of ferroelectric layers are considered to create a more realistic modeling. The proposed research work also provides an in-depth study of the electrical properties of the GAA-based Nanowire FeFET, exploring important variables including transconductance, subthreshold swing, as well as a threshold voltage. The analytical insights derived from the mathematical framework are consistent with the simulated results obtained with the ATLAS 3D simulator. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
47. Dielectric, magnetic, and magnetodielectric change mechanisms in Y-type BaSrZn2Fe12O22 ceramics regulated by doping Al3+ and Ga3+ ions.
- Author
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Sun, Meng, Yang, Yang, Zhou, Jian-Ping, Jiang, Qinghui, Wang, Weijia, and Chen, Xiao-ming
- Subjects
- *
ELECTRON spin , *MAGNETIC fields , *HYSTERESIS loop , *PHASE diagrams , *MAGNETIC properties - Abstract
We systematically investigated the dielectric, magnetic, and magnetodielectric (MD) properties of Y-type hexaferrite doped with Al3+ and Ga3+ ions. Al3+ ions preferentially enter the spin-up octahedral lattice sites while Ga3+ ions occupy the spin-down octahedral lattice sites first and then, enter the spin- octahedral sites with the increase in doping amount. The initial magnetization reaches saturation from outside of the hysteresis loops, exhibiting a non-collinear spin order. The step-like increase in magnetization with magnetic field indicates the ferroelectric changes in longitudinal conical spin order. The positive MD effect at low temperatures and the negative MD effect after warming for the doped samples are controlled by non-collinear spin ordering and electron hopping, respectively. The Al-doped and Ga-doped samples exhibit different ferroelectric behaviors driven by magnetic fields. Their ferroelectric phase diagrams were proposed on the basis of magnetic and MD properties. The results associate the physical properties with the doped ions in Y-type hexaferrite. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Measuring anisotropy field of patterned soft magnetic films by anisotropic ferromagnetic resonances.
- Author
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Li, Na, Zhang, Fangyuan, Zhao, Rongzhi, Bo, Guohao, Lei, Ting, Zhang, Jian, and Zhang, Xuefeng
- Subjects
- *
MAGNETIC films , *FERROMAGNETIC resonance , *ELECTROMAGNETIC devices , *HYSTERESIS loop , *MAGNETIC fields - Abstract
Patterned magnetic films have been applied widely in communication technology for meeting the development of miniaturization and high frequency. However, there has been some debate about the measuring of the anisotropy field, which is significant for deciding the electromagnetic performance. In the paper, we proposed the measurement of the anisotropy field using anisotropic ferromagnetic resonances in patterned permalloy magnetic films. The anisotropy in patterned permalloy with different magnetic stripe widths can be observed qualitatively by the hysteresis loop along in-plane x and y directions, which induces the anisotropic ferromagnetic resonant behaviors. The anisotropy field can be calculated quantificationally by fitting the Kittel equation when the single resonant peak appears under applied magnetic fields. The values of the anisotropy field obtained by anisotropic ferromagnetic resonances are on the lower side to compare with the ones obtained by the energy difference between easy anis and hard axis. Our results can provide an extra method for measuring the anisotropy field, which can be useful for designing electromagnetic devices and potential applications in next-generation wireless communication. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Hysteresis loop variations induced by nitrogen flow rate in solution-based VO2 films.
- Author
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Bi, Xinyue, Guo, Yuxian, Qu, Haojie, Zhang, Donghui, Kong, Huifang, Liu, Yanfang, and Zhang, Haitao
- Subjects
- *
PARTICLE size distribution , *PHASE transitions , *HYSTERESIS loop , *TRANSITION temperature , *VANADIUM dioxide - Abstract
Due to the special semiconductor-to-metal transition (SMT) properties, vanadium dioxide (VO2) film has attracted tremendous interest for both the fundamental correlated electronic structure studies and the phase-change devices applications. It is known that the SMT features of VO2 are always closely associated with the film preparation, which becomes an important issue for the research in this field. In the current study, we explored the preparation of VO2/Al2O3 films by adopting the sol-gel method in conjunction with a subsequent annealing process. The effects of nitrogen flow rate on the structure, composition, morphology, and electrical properties of the VO2 films were investigated. Results showed that V2O5 film was formed without nitrogen protection. As the nitrogen flow rate increased from 100 mL/min to 500 mL/min, the films exhibited a polycrystalline structure with VO2 (020) preferred orientation. Simultaneously, the V4+ content within the film remained largely constant, while the surface grains gradually enlarged, accompanied by a more dispersed grain size distribution. Moreover, the increased nitrogen flow rate led to a consistent reduction in both the transition temperature during the heating process and the hysteresis width of the film. The asymmetry of the hysteresis loop of the thin film was also enhanced, which was closely related to the grain size distribution on the surface of the film. These findings not only elucidated the influence of nitrogen flow rate on the phase transition properties of VO2 during annealing, but also offered a novel insight into the regulation of VO2 phase transitions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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50. Photocatalytic Degradation of Rhodamine B Using ZnCo2O4/N-doped g-C3N4 Nanocomposite.
- Author
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Nasir, Kawthr H. and Alshamsi, Hassan A.
- Subjects
- *
PHYSICAL & theoretical chemistry , *RHODAMINE B , *PHOTODEGRADATION , *VISIBLE spectra , *HYSTERESIS loop , *IRRADIATION - Abstract
In this study, g-C3N4, ZnCo2O4, N-doped g-C3N4, ZnCo2O4/g-C3N4 and ZnCo2O4/N-doped g-C3N4 nanopowders were synthesized by the hydrothermal method and applied as photocatalysts to degrade Rhodamine B under visible light illumination in an aqueous solution. The as synthesized nanostructures were characterized via FT-IR, XRD, FE-SEM, EDS, TEM, UV–Vis DRS, and BET/BJH techniques. The XRD analysis revealed the successful synthesis of cubic ZnCo2O4 and nanolayered g-C3N4. The BET/BJH analysis exhibited that all samples show a typical Type-III isotherm and H3-type hysteresis loops. The FTIR and EDX analyses validated the formation of the presumed nanomaterials. UV–Vis DRS results indicated that the loading of ZnCo2O4 on N-doped g-C3N4 effectively shifted absorption edge to longer wavelengths. The morphological study showed sufficient distribution of ZnCo2O4 nanoparticles onto g-C3N4 nanosheets. The photocatalytic degradation results show that photocatalytic performance can be enhanced by optimizing operating conditions, including irradiation time, catalyst dosage, RhB concentration and solution pH. The ZnCo2O4/N-doped g-C3N4 showed the highest photodegradation efficiency of 92.34% RhB degradation in 60 min illumination. In addition, the results of scavenging study indicate that hydroxyl radicals (•OH) play a main role in the photodegradation process. The kinetic study demonstrates that the photodegradation of RhB follows pseudo first order kinetic model. The recyclability study showed that the ZnCo2O4/N-doped g-C3N4 nanocomposite retained 83.38% of its initial activity after reuse for five cycles. Furthermore, at optimum conditions, the COD removal efficiency was 79.55%, indicating that most of dye molecules are degraded. Therefore, the current designed system can be regarded as an efficient and effective approach for the remediation of water contaminants. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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