共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
《Materials Science & Technology》2013,29(11):1312-1315
AbstractThe process of ferroelectric/ferroelastic switching is rate dependent as evidenced by the frequency dependence of the coercive field/stress in polarisation/strain–electric field/stress loops. The rate dependence of domain switching has been investigated in different compositions of ferroelectric/ferroelastic perovskites by studying their stress–strain hysteresis loops. Stress–strain loops were generated by applying a static compressive load and then superimposing cyclic compressive loads of different amplitudes and frequencies. The stress–strain loops were fitted using a Rayleigh type relationship, whose parameters characterise the intrinsic and extrinsic contributions to the strain. Using these parameters, the rate dependence of the extrinsic domain wall contribution was investigated. 相似文献
3.
Ferroelectric oxides, such as Pb(Zr,Ti)O(3), are useful for electronic and photonic devices because of their ability to retain two stable polarization states, which can form the basis for memory and logic circuitry. Requirements for long-term operation of practical devices such as non-volatile RAM (random access memory) include consistent polarization switching over many (more than 10(12)) cycles of the applied electric field, which represents a major challenge. As switching is largely controlled by the motion and pinning of domain walls, it is necessary to develop suitable tools that can directly probe the ferroelectric domain structures in operating devices-thin-film structures with electrical contacts. A recently developed synchrotron X-ray microdiffraction technique complements existing microscopic probes, and allows us to visualize directly the evolution of polarization domains in ferroelectric devices, through metal or oxide electrodes, and with submicrometre spatial resolution. The images reveal two regimes of fatigue, depending on the magnitude of the electric field pulses driving the device: a low-field regime in which fatigue can be reversed with higher electric field pulses, and a regime at very high electric fields in which there is a non-reversible crystallographic relaxation of the epitaxial ferroelectric film. 相似文献
4.
A. Gruverman 《Journal of Materials Science》2009,44(19):5182-5188
In this study, we review recent advances in PFM studies of micrometer scale ferroelectric capacitors, summarize the experimental
PFM-based approach to investigation of fast switching processes, illustrate what information can be obtained from PFM experiments
on domains kinetics, and delineate the scaling effect on polarization reversal mechanism. Particular attention is given to
PFM studies of mechanical stress effect on polarization stability. 相似文献
5.
The nucleation and growth of domains is investigated near a stationary crack tip in a single crystal of ferroelectric material. The phase-field approach, applying the material polarization as the order parameter, is used as the theoretical modeling framework and the finite element method is used for the numerical solution technique. The electromechanical form of the J-integral is appropriately modified to account for the polarization gradient energy terms, and analyzed to illustrate the amount of shielding, or lack thereof, due to domain switching at the crack tip. It is shown that the nucleation of domains near the crack tip due to applied electric field is affected by applied stress. However, the crack-tip energy release rate can change significantly between the instant of domain nucleation and the final equilibrium domain configuration. Implications of these results for ferroelectric single crystal fracture criteria are discussed. 相似文献
6.
Shihai Zhang Rob J. Klein Kailiang Ren Baojin Chu Xi Zhang James Runt Q. M. Zhang 《Journal of Materials Science》2006,41(1):271-280
To elucidate the molecular origin of the polarization dynamics in the ferroelectric relaxor poly(vinylidene fluoride—trifluoroethylene-chlorofluoroethylene)
(P(VDF-TrFE-CFE)) terpolymer, a broadband dielectric study was carried out in the frequency range from 0.01 Hz to 10 MHz and
temperatures from −150°C to 120°C for the terpolymer and a normal ferroelectric P(VDF-TrFE) copolymer. The relaxation processes
were also studied using dynamic mechanical analysis. It was shown that in the terpolymer, which was completely converted to
a ferroelectric relaxor, there is no sign of the relaxation process associated with the ferroelectric-paraelectric transition
which occurs in the P(VDF-TrFE) copolymer. In the copolymer, three additional relaxation processes have been observed. It
was found that the relaxation process βa, which was commonly believed to be associated with the glass transition in the amorphous phase, in fact, contains significant
contribution from chain segment motions such as domain boundary motions in the crystalline region. In the temperature range
studied, the terpolymer exhibits the latter three relaxation processes with the one (termed βr) near the temperature range of βa significantly enhanced. This is consistent with the observation that in conversion from the normal ferroelectric to a ferroelectric
relaxor, the macro-polar domains are replaced by nano-polar-clusters and the boundary motions as well as the reorientation
of these nano-clusters generate the high dielectric response. The experimental data also reveal a broad relaxation time distribution
related for the βr process whose distribution width increases with reduced temperature, reflecting the molecular level heterogeneity in the
crystalline phase due to the random introduction of the CFE monomer in the otherwise ordered macro-polar domains. The random
interaction among the nano-clusters as well as the presence of the random fields produces ferroelectric relaxor behavior in
the terpolymer. 相似文献
7.
Shin H Lee KM Moon WK Jeon JU Lim G Pak YE Park JH Yoon KH 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(4):801-807
The feasibility of utilizing PZT films as future data storage media was investigated using a modified AFM. Applying voltages between a conductive AFM tip and the PZT films causes the switching of ferroelectric domains. The domains are observed using an EFM imaging technique. The experimental results and calculations revealed that the electrostatic force generated between the polarized area and the tip is a main contributor for the imaging of the polarized domains. The written features on ferroelectric films were less than 100 nm in diameter, implying the possibility of realizing data storage devices with ultra-high area density. The disappearance of the polarized images without any applied voltage was observed, which is a drawback in this application of PZT thin films. 相似文献
8.
9.
Hongyang Zhao Kang Cai Zhenxiang Cheng Zhibin Ma Hideo Kimura Tingting Jia 《Journal of Materials Science: Materials in Electronics》2016,27(6):5613-5617
Ferroelectric/Piezoelectric K0.5Bi4.5Ti4O15 (KBT) film was fabricated by pulsed laser deposition method and confirmed by ferroelectric, dielectric measurements and local butterfly-type piezoresponse hysteresis loops. Importantly, ferroelectric domain switching by both electrical field and mechanical force in KBT film was demonstrated. The dark and bright contrast represents the PFM response of the up and down polarized domains, which can be written by a dc bias of ±12 V or a mechanical force of 40–50 nN. The successful demonstration of mechanical force switching of ferroelectric domain in KBT film other than electric field provides a novel mean for information storage and sensors. 相似文献
10.
This paper examines the switching process occuring in ferroelectric and ferroelastic single crystals under electro-mechanical loadings. Ferroelectrics undergoing a cubic to tetragonal phase transition are considered. The single crystal energy has three origins: elastic, electric and the incompatibilities of the spontaneous strain and electric displacement fieds between domains. The stress and electric fields fluctuate and present jumps at the domain walls. As a consequence, they induce electro-elastic interaction energy. Thus, it involves dissipation that the present work aims to capture through a micromechanical approach. 相似文献
11.
R. Yimnirun N. Triamnak M. Unruan S. Wongsaenmai A. Ngamjarurojana Y. Laosiritaworn S. Ananta 《材料科学与工程学报》2007,25(6):833-836,849
Dielectric and ferroelectric properties of complex perovskite PZT-PZN ceramic system were investigated under the influence of the compressive stress. The results showed that the dielectric properties, i.e. dielectric constant ( εr ) and dielectric loss ( tan δ), and the ferroelectric characteristics, i.e. the area of the ferroelectric hysteresis loops, the saturation polarization ( P(sat) ), and the remnant polarization (Pr) changed significantly with increasing compressive stress. These changes depended strongly on the ceramic compositions. The experimental results on the dielectric properties could be explained by both intrinsic and extrinsic domain-related mechanisms involving domain wall motions, as well as the de-aging phenomenon. The stress-induced domain wall motion suppression and non-180° ferroelectric domain switching processes were responsible for the changes observed in the ferroelectric parameters. In addition,a significant decrease in those parameters after a cycle of stress was observed and attributed to the stress induced decrease in switchable part of spontaneous polarization. This study clearly show that the applied stress had significant influence on the electrical properties of complex perovskite ceramics. 相似文献
12.
Woltman SJ Eakin JN Crawford GP Zumer S 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(12):3789-3799
Uniform alignment of ferroelectric liquid-crystal domains encapsulated by a polymer binder was established through a holographic exposure process. The refractive index modulation in these thin films is modeled as a phase grating that can be electrically addressed to erase the optical diffractive properties. A phenomenological model is developed to take into account a distribution of domain sizes and an effective field that stabilizes the ferroelectric liquid-crystal domains. A diffraction model successfully predicts changes in normalized intensities for first-order diffraction with applied field. These gratings demonstrate microsecond-scale response and relaxation times for various grating pitch sizes between approximately 3 and approximately 12 microm. 相似文献
13.
Numerical analysis of ferroelectric/ferroelastic domain switching in ferroelectric ceramics 总被引:1,自引:0,他引:1
A numerical approach predicting the behavior of ferroelectric ceramics under electric field and mechanical loading is proposed in this paper. In the model, macroscopic properties of ferroelectric ceramics are determined by microscopic structures. Ferroelectric ceramics are seen to be composed of many domains with different orientations, and domain switching is the source of the nonlinear constitutive behavior of the ferroelectric ceramics. Numerical calculations based on the model were carried out, and the computational results are compared with the experimental results, which shows the two sets of results consist with each other. The calculation approach can provide a guidance for the ceramics component design. 相似文献
14.
Sang-Joo Kim 《Acta Mechanica》2012,223(10):2091-2105
A constitutive model that can be used to predict creep behavior of ferroelectric polycrystals at room and high temperatures is proposed. The model consists of the Gibbs free energy function with normal distribution and a switching evolution law with critical driving force. Linear moduli in the free energy function and switching parameters in the switching law are assumed to be linearly dependent on temperature. A ferroelectric polycrystal is modeled by an agglomerate of 210 single crystallites. Compressive stress and electric field-induced creep behavior as well as polarization hysteresis and strain butterfly responses of the model are calculated and compared with experimental observations. 相似文献
15.
Manipulation of ferroic order parameters, namely (anti‐)ferromagnetic, ferroelectric, and ferroelastic, by light at room temperature is a fascinating topic in modern solid‐state physics due to potential cross‐fertilization in research fields that are largely decoupled. Here, full optical control, that is, reversible switching, of the ferroelectric/ferroelastic domains in BiFeO3 thin films at room temperature by the mediation of the tip‐enhanced photovoltaic effect is demonstrated. The enhanced short‐circuit photocurrent density at the tip contact area generates a local electric field well exceeding the coercive field, enabling ferroelectric polarization switching. Interestingly, by tailoring the photocurrent direction, via either tuning the illumination geometry or simply rotating the light polarization, full control of the ferroelectric polarization is achieved. The finding offers a new insight into the interactions between light and ferroic orders, enabling fully optical control of all the ferroic orders at room temperature and providing guidance to design novel optoferroic devices for data storage and sensing. 相似文献
16.
In order to study the dynamic behaviour of domains during poling, the acoustic emission (AE) characteristics of two La-modified PbTiO3 ferroelectric ceramics in which 90° and 180° domains were respectively dominant have been investigated. One sample was a 15 mol% La-doped ceramic with a high tetragonality ratio (c/a=1.021) and the other was a 24 mol% La-doped ceramic where the tetragonality ratio was close to unity (c/a=1.007). The acoustic emission behaviour of the former sample consisted of both burst as well as continuous emission, with the latter sample mainly showing continuous emission. Energy distributions made it possible to distinguish between the AE signals resulting from 90° and 180° domain switching. From the observed results, it was confirmed that most of the AE occurred due to 90° domain switching. By introducing an alternative switching behaviour for the 90° domains, the behaviour of the AE generation during poling could be explained. 相似文献
17.
18.
Shih-Wei Chen 《Thin solid films》2010,519(1):499-6159
Bismuth ferrite (BiFeO3, BFO) thin films were spin-coated on Pt/Ti/SiO2/Si substrates by a chemical solution deposition method. The ferroelectric BFO films annealed at 500 °C and 550 °C were found to possess unipolar resistive switching behaviors. The resistance ratio of the high resistance state (HRS) to the low resistance state (LRS) of the unipolar resistance switching is about 103 for the ferroelectric BFO films. The conduction mechanisms are concluded to be space charge-limited conduction for the initial state and Ohmic conduction for the LRS. As for the HRS, the Poole-Frenkel emission fits well in the whole voltage region. Traps composed of oxygen vacancies are considered to play a key role in forming conducting paths. The relaxation time of electronic carriers is much shorter than that of ionic oxygen vacancies; therefore, the resistance switching is considered more probably due to carrier injection and emission through the Poole-Frenkel model after forming. 相似文献
19.
Lead zinc niobate (Pb(Zn1/3Nb2/3)O3, PZN) based ceramics are prepared by using conventional mixing oxide and complex phase reaction-sintering ceramic techniques. From the results of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it is clear that these two fabrication processing routes produce different microstructures and ferroelectric domains in the same Pb(Zn1/3Nb2/3)O3–BaTiO3–Pb(Zr0.4Ti0.6)O3 composition. Furthermore, different phase transitions are observed for the temperature dependence of the dielectric permittivity that can be confirmed by differential scanning calorimetry (DSC). Different polarization switching characteristics are also examined by using high field-induced strain and ferroelectric hysteresis loop. It is suggested that the distribution of the inner stress and domain configuration should be related with the fabrication processing of ferroelectric ceramics. 相似文献
20.