Typical Hysteresis Loops Research Articles

Structural, Magnetic, and Dielectric Spectroscopy Investigations of Multiferroic Composite Based on Perovskite–Spinel Approach

Multiferroic composite materials with the nominal composition (La0.8Gd0.2FeO3)1−x(Mn0.5Cu0.5Fe2O4)x, x = 0.0≤x≤1 were prepared using the co-precipition method. XRD, FTIR and Raman were utilized to investigate the structure phase, microstructural characteristics, vibrational bands. The optical properties were analyzed; the VSM was used to investigate the magnetic properties of the composites. Broadband dielectric spectroscopy is employed to investigate the dielectric and electrical performance of the prepared multiferroic composites. Rietveld refinement of the XRD patterns confirmed the orthorhombic phase for lanthanum gadolinium iron oxide (La0.8Gd0.2FeO3) and cubic phase for manganese copper ferrite (Mn0.5Cu0.5Fe2O4). The crystallite size of LGFO phase pointed out that it increases with increasing the MCFO phase, while the microstrain found to decline. The FTIR results elucidated the tetrahedral and octahedral bands. The deduced optical properties revealed that the samples have optical energy gap in the range 4.18 −4.5 eV. The magnetic properties revealed that the composites exhibit typical ferromagnetic hysteresis loops, indicating the presence of ordered magnetic structure. The frequency dependence of permittivity ε′(f) and real part of complex conductivity, σ′(f) exhibits a development of a net of micro-capacitors like behavior that stores charge carriers.

Comparative study on (Na0.47Bi0.47Ba0.06)0.95A0.05TiO3 (A = Sr2+/Ca2+) lead-free ceramics: Scaling behavior of ferroelectric hysteresis loop

Scaling behavior of dynamic hysteresis of (Na0.47Bi0.47Ba0.06)0.95A0.05TiO3 (A = Sr2+/Ca2+) (expressed as BNBT-Sr and BNBT-Ca, respectively) lead-free ceramics was comparatively studied. BNBT-Ca exhibits typical ferroelectric hysteresis (polarization vs electric field, P–E) loops, while BNBT-Sr shows pinched P–E loops. The two samples' electric field and frequency-dependent dynamic hysteresis behavior were systematically investigated. The dopants difference (Sr2+/Ca2+) produces different scaling behavior of dynamic hysteresis, which is related to the electric field-induced phase transition and domain size between BNBT-Sr and BNBT-Ca.

Opening magnetic hysteresis via improving the planarity of equatorial coordination by hydrogen bonding.

Through a mixed-ligand strategy, the structural change from a discrete dinuclear DyIII cluster to a one-dimensional polymeric chain was achieved, maintaining the two magnetic entities with the same {Dy(dppbO2)2(H2O)5} (dppbO2 = 1,4-butylenebis(diphenylphosphine oxide)) core structure. Since the hydrogen bonding between the equatorial coordinated water molecules and the guests/solvents/anions is distinct, the local geometry and the equatorial planarity of the first coordination sphere of the central DyIII ion become slightly different caused by the second coordination sphere. As a result, the dinuclear compound shows typical butterfly-shaped hysteresis loops, while it significantly opens at zero magnetic field up to 11 K for the 1D polymer, which is unprecedented in coordination polymers. Our experimental observations and theoretical analysis indicate that the hydrogen bonding leads to the fine-tuning of certain bond lengths and angles of the coordination environment, as well as the crystal field to a certain extent, revealing that the second coordination sphere affects the first coordination sphere by hydrogen bonding.

Surface properties of nano mesoporous lanthanum oxide synthesized by sol-gel method

This study investigates surface properties like surface acidity/basicity, surface reducibility, surface area, and porosity of nano mesoporous lanthanum oxide (La2O3) synthesized by the sol–gel method. X-ray diffraction (XRD) analysis confirms the formation of nanocrystalline hexagonal La2O3 at 800 °C. Fourier transform infrared spectra (FT-IR) shows the peaks corresponding to surface carbonate and surface water on La2O3. Morphology of La2O3 was studied by transmission electron microscopy (TEM). The surface acidity of La2O3 was measured by temperature-programmed desorption (TPD-NH3) analysis and surface basicity by TPD-CO2. TPD profiles show the presence of medium and strong acidic and basic sites on the surface of La2O3. La2O3 has more surface acidity compared to surface basicity. Temperature programmed reduction (H2-TPR) analysis indicates good stability of La2O3 towards reduction. The values of H2 consumption indicate a greater amount of reducible species on the surface. Surface area and porosity measurements were done using Braunauer-Emmet-Teller (BET) analysis. The pore size distribution curve is also determined from the Barrett-Joyner-Halenda (BJH) adsorption/ desorption isotherm. La2O3 is found to be mesoporous with pore diameter of 20.6 nm and has wide pore size distribution between 5 and 50 nm. Typical type IV isotherm with H3 type hysteresis loops at a high P/P0 value is observed for La2O3.

Softening of antiferroelectric order in a novel PbZrO3-based solid solution for energy storage

PbZrO3-based antiferroelectric (AFE) materials have received growing attention for their attractive energy storage performance. However, a major drawback of PZ is its high critical electric field (Ecr) which makes it difficult to switch the antiparallel dipoles therein so as to be useful. Therefore, softening of AFE order in PbZrO3 is thought to be a promising approach for its practical applications. In this work, a new binary AFE solid solution of (1-x)PbZrO3-xPb(Mg1/2Mo1/2)O3 (PZ-PMM), with x = 0.00–0.10, was successfully synthesized in form of ceramics via the solid-state reaction method. The effect of chemical modification by introducing Pb(Mg1/2Mo1/2)O3 on the crystal structure, phase transition behavior and electrical properties of the PbZrO3 ceramics are investigated systemically. It is found that a perovskite phase with orthorhombic Pbam symmetry is preserved at room temperature for all the compositions studied, and a broadened ferroelectric intermediate phase exists between the paraelectric (PE) and the antiferroelectric phases of the PZ-PMM solid solution. At 160 °C, typical double hysteresis loop can be displayed for all the compositions. Most importantly, the maximum electric field-induced polarization is significantly increased, whereas the critical field is decreased with increasing PMM content, suggesting a remarkable softening effect of the antiferroelectric order in PZ due to some degree of dipole frustration. This work could bring about the development of a new series of PZ-based solid solutions for energy storage applications in the future.

The effect of thickness-dependent strain relaxation on magnetoelectric behaviors for highly c-axis oriented BiFeO3 films on Si substrate

The thickness-dependent strain-relaxation behavior and the associated impacts upon the magnetic, electric properties and magnetoelectric coupling effect for the highly c-axis oriented BiFeO3 (BFO) film films grown on (001) oriented Si substrate were studied. The result shown that the value of remnant polarization and coercive field were suppressed as the strain relaxes with increasing thickness. The BFO films also presented typical weak ferromagnetic hysteresis loops with a low coercive field and small remnant magnetization, and the saturated magnetization and remnant magnetization decreasing with increasing film thickness. The room temperature dynamic magnetoelectric coupling was approved by the transverse magnetoelectric voltage coefficients, which also decreased with strain relaxation due to the increase of thickness, and the maximum was around 265 mV/cm.Oe when the film thickness is 50 nm.

Characterization of geochemical properties and factors controlling the pore structure development of shale gas reservoirs

The pore structure is an important parameter to understand the transport and storage capacities in shale. There is very limited research reported on the controlling factors of pore development in lacustrine shales to date. This study investigated pore developments and hydrocarbon generation potential of lacustrine Roseneath and Murteree shale formations. Although these shale formations are proven shale gas reservoir in the Cooper Basin, Australia, pore development studies are still rare. The geochemical properties measured on core samples include total organic contents (TOC), thermal maturity, hydrocarbon generation potential, and mineral composition by X-ray diffraction (XRD). Field-emission scanning electron microscopy (FE-SEM), Focused Ion Beam milling scanning electron microscopy (FIB-SEM), and low-pressure nitrogen adsorption-desorption isotherm experiments were used to quantify and qualify pore structure. Furthermore, the factors were analyzed that control pore development through statistical analysis. The results indicate that organic contents for the Roseneath shales (0.9%–1.74% Ro%) and Murteree shales (1%–1.7% Ro%) range between 0.81% and 5.36% and 0.51%–6.69%, respectively. The dominant mineral phases are quartz, clay (Illite, Kaolinite), and siderite, with variable quantities of the studied formations. Rock-Eval pyrolysis suggests Kerogen Type III and implies mostly late oil generation to dry gas generation potential in both shale formations. In Roseneath shale, total surface area (SSA) and total pore volume (TPV) varies from 2.25 cm2/g to 5 cm2/g and 0.005 cm3/g – 0.02 cm3/g, respectively. In Murteree shale, SSA and TPV vary from 3.5 cm2/g to 6.35 cm2/g and 0.005 cm3/g to 0.032 cm3/g, respectively. The pores exhibit unimodal to bimodal distribution with peaks at 2–4 nm, 90–120 nm, and 170–180 nm. The mesopores are dominant in studied formations, followed by macropores and micropores. Mesopores have the largest contribution to specific surface area and pore volume. The desorption hysteresis loop on the N2 adsorption-desorption curve indicates the presence of permeable and impermeable pores, as most of the samples belong to H2 and H3 type hysteresis loop. The pore size of intraparticle and interparticle various greatly; however, the pores with a diameter of 2.5 nm, 18 nm and 49 nm are common in both formations. The organopores contribute to micropores' development, and most organic pores have a pore diameter of 1.5 nm and 1.8 nm. The total pore volume (TPV) and specific surface area (SSA) are positively correlated with organic matter contents, quartz, and thermal maturity in both shale formations. However, clay minerals are positively correlated with SSA and TPV, which indicate that clay minerals have a significant contribution to Roseneath shale's pore development. The siderite mineral contributes to intraparticle pores development and positively correlated with SSA and TPV in Murteree shale. The thermal maturity significantly enhances pore's development by creating organopores and inorganic pores in both shales, as evidenced through statistical analysis and image analysis. The study has significant importance in understanding the pore structure and gas storage mechanism in shale.

Magnetic Remanence of Stainless Steel and Titanium Alloy Orthopaedic Implants

Stainless steel and titanium alloys are common materials for orthopaedic implants. However there is a lack of information and studies on magnetic remanence of implants used in clinical practice. The aims of this study are to investigate the composition and the presence of magnetic remanence for these two orthopaedic implant materials. These two factors may cause implant instability and heat problems as well as degradation of the images quality if the patients undergo magnetic resonance imaging (MRI) examination. The magnetic hysteresis loop and remanence status of stainless steel and titanium alloy orthopaedic implants were investigated with a vibrating sample magnetometer (VSM). Both samples of stainless steel and titanium alloy had been exposed to external magnetic fields up to 1 T (10000 G) and 1.4 T (14000 G), respectively. The compositions of these two orthopaedic implant materials were studied using a scanning electron microscope with energy dispersive X-ray analysis (SEM-EDX). The results of the study demonstrated that ferrous and nickel compositions in stainless steel alloy orthopaedic implants contributed to the residual magnetism, as shown in the hysteresis loop. The titanium alloy orthopaedic implant sample does not contain any ferromagnetic elements. After exposure to a magnetic field, the stainless steel values of retentivity, coercivity and magnetisation are significantly higher compared to those of the titanium alloy. The stainless steel orthopaedic implant sample demonstrates a typical hysteresis loop that suggests the existence of magnetic remanence. In contrast, the titanium alloy orthopaedic implant sample showed no significant remanence phenomenon. By considering the existence of magnetic remanence in the implant is important as potential effect on the MRI image quality.

Enhanced H2 evolution via photocatalytic water splitting using mesoporous TiO2/RuO2/CuO ternary nanomaterial

Mesoporous TiO2/RuO2/CuO (0.05, 0.1, 0.5, and 1%) ternary nanosystem have been synthesized via sol-gel route using pluronic P123 as structure directing agent. The diffuse reflectance spectra (DRS) indicated a considerable red shift for mesoporous TiO2/RuO2/CuO 1% nanomaterial with a band gap energy value of 2.5 eV compared to 2.9 eV for mesoporous TiO2/RuO2 0.5%. The N2 sorption studies using BET (Brunauer Emmet Teller) revealed the type IV adsorption isotherms for the prepared samples with H3 type hysteresis loop establishing the formation of mesoporous structure. The specific surface area of mesoporous TiO2/RuO2/CuO 1% and TiO2/RuO2 0.5% were 53 and 39.5 m2/g, respectively. The X-ray photoelectron spectroscopic analysis of the ternary material mesoporous TiO2/RuO2/CuO 1% confirmed the existence of Ru, Cu, O, and Ti in this material which was further supported through high resolution transmission electron microscopic (HR-TEM) and energy dispersive x-ray spectroscopic (EDS) studies. From PL spectra it followed that there was a substantial reduction in PL intensity of the ternary nanomaterial TiO2/RuO2/CuO 1% compared to mesoporous TiO2 and mesoporous TiO2/RuO2 0.5%, which confirmed the lower electron-hole recombination in this ternary nanomaterial, which was further supported through photocatalytic H2 evolution studies using these catalysts. From the comparative photocatalytic H2 evolution conducted using the catalysts mesoporous TiO2/RuO2/CuO 1% (0.05, 0.1, 0.5 and 1%), mesoporous TiO2/RuO2 0.5%, and mesoporous TiO2, the maximum H2 evolution was observed with mesoporous TiO2/RuO2/CuO 1%. The H2 evolution was monitored by varying various parameters such as effect of catalyst used, catalyst weight, concentration of CuO loaded, amount of sacrificial agent, chain length of alcohols as sacrificial agent, and found remarkable influence in hydrogen generation. Continuous irradiation of the photocatalyst mesoporous TiO2/RuO2/CuO 1% for 18 hours resulted in the maximum evolution of 20.7 mmol of H2. The present study demonstrated the excellent photocatalytic performance of the newly synthesized catalyst, mesoporous TiO2/RuO2/CuO ternary nanomaterial.

Restoring-force model for HFC-filled CFS shear walls subjected to in-plane cyclic loading

High-strength foamed concrete (HFC)-filled cold-formed thin-walled steel (CFS) shear wall, as a new-type CFS shear wall, is the major lateral load-resisting member for multi-storey CFS structures. A cyclic restoring-force model has been used extensively in seismic analysis of these shear walls. Experimental study is conducted to investigate the characteristics of hysteretic and skeleton curves, and analyzed the effect of parameter variation on the characteristics. Results indicate that the skeleton curves displayed obvious non-linear characteristics, and the hysteresis loops exhibited significant stiffness and strength deterioration with slipping and pinching effect. By analyzing the typical test skeleton curve and hysteresis loop, seven feature points were defined to represent the hysteretic curve characteristic. A multi-linear restoring-force model was developed to simulate the hysteretic curves and implement in MATLAB software. Eleven representative hysteretic curves obtained from experimental data and the literatures were compared with that of the developed model. The calculated skeleton curves and hysteresis loops agreed with the test results in terms of the evaluation of the feature points and accumulated energy dissipation.

Copper/Nickel-Decorated Olive Pit Biochar: One Pot Solid State Synthesis for Environmental Remediation

Developing micro- and nanomaterials for environmental pollution remediation is currently a pertinent topic. Among the plethora of strategies, designing supported nanocatalysts for the degradation of pollutants has achieved prominence. In this context, we are addressing one of the UN Sustainable Development Goals by valorizing agrowaste as a source of biochar, which serves as a support for bimetallic nanocatalysts. Herein, olive pit powder particles were impregnated with copper and nickel nitrates and pyrolyzed at 400 °C. The resulting material consists of bimetallic CuNi-decorated biochar. CuNi nanocatalysts were found to be as small as 10 nm and very well dispersed over biochar with zero valent copper and nickel and the formation of copper–nickel solid solutions. The biochar@CuNi (B@CuNi) exhibited typical soft ferromagnet hysteresis loops with zero remanence and zero coercivity. The biochar@CuNi was found to be an efficient catalyst of the reduction in methyl orange (MO) dye, taken as a model pollutant. In sum, the one-pot method devised in this work provides unique CuNi-decorated biochar and broadens the horizons of the emerging topic of biochar-supported nanocatalysts.

A Metal-Free Molecular Antiferroelectric Material Showing High Phase Transition Temperatures and Large Electrocaloric Effects.

Antiferroelectric (AFE) materials, featuring an antiparallel alignment of electric dipoles in the adjacent sublattices, are keeping a great promise toward solid-state refrigeration applications on account of their electrocaloric (EC) effects. Although extensive studies have been performed on inorganic oxide counterparts (e.g., PbZrO3 and AgNbO3), metal-free molecular AFE alternatives with the above-room-temperature EC activities are quite scarce but urgently demanded in terms of environmental issues. Herein, we present a new metal-free molecular AFE, cyclohexylmethylammonium bromide (CMB), which exhibits the unusual antiferroelectric-ferroelectric-paraelectric phase transitions around 364 and 368 K upon heating. The phase transition temperatures are much higher than the majority of known molecular AFE materials. The practical utilization level of electric polarization (∼6 μC/cm2) is clearly evidenced by the typical double polarization-electric field hysteresis loops. Strikingly, large positive and negative EC responses with the temperature changes (ΔT) of 4.2 and -3 K are achieved under an electric field of 20 kV/cm. The origin of its antiferroelectricity and EC properties is elucidated by the antipolar reorientation of cations along with displacement of bromine anions, being distinct from the known mechanism of inorganic oxides. Such intriguing AFE behaviors, including large polarization and EC effects, reveal great potentials of CMB for the solid-state refrigeration. This study sheds light on further exploration of new AFE candidates toward environmentally friendly solid-state cooling devices.

Design and multistability analysis of five-value memristor-based chaotic system with hidden attractors* *Project supported by the National Natural Science Foundation of China (Grant No. 61203004), the Natural Science Foundation of Heilongjiang Province, China (Grant No. F201220), and the Heilongjiang Provincial Natural Science Foundation of Joint Guidance Project (Grant No. LH2020F022).

A five-value memristor model is proposed, it is proved that the model has a typical hysteresis loop by analyzing the relationship between voltage and current. Then, based on the classical Liu–Chen system, a new memristor-based four-dimensional (4D) chaotic system is designed by using the five-value memristor. The trajectory phase diagram, Poincare mapping, bifurcation diagram, and Lyapunov exponent spectrum are drawn by numerical simulation. It is found that, in addition to the general chaos characteristics, the system has some special phenomena, such as hidden homogenous multistabilities, hidden heterogeneous multistabilities, and hidden super-multistabilities. Finally, according to the dimensionless equation of the system, the circuit model of the system is built and simulated. The results are consistent with the numerical simulation results, which proves the physical realizability of the five-value memristor-based chaotic system proposed in this paper.

Synthesis and characterisation of lead free BaFe12O19 –(K0.5Na0.5)NbO3 magnetoelectric composites, and the comparison of various synthetic routes

Polycrystalline lead-free (1-x)BaFe12O19–x(K0.5Na0.5)NbO3 magnetoelectric ceramic composites (x = 10, 20 and 30 wt%) were fabricated for the first time, comparing various synthesis techniques, namely solid state reaction, sol-gel, co-precipitation and citrate combustion methods for the synthesis of the ferrite phase. As well as the four synthesis routes, comparisons were made between uniaxial pressing and cold isostatic pressing of the samples prior to sintering at 1200 °C/2 h. Formation of separate magnetic hexaferrite BaFe12O19 (BaM) and ferroelectric (K0.5Na0.5)NbO3 (KNN) phases in the composites was confirmed using x-ray diffraction. The microstructural features revealed distribution of BaM and KNN grains in all the composite systems. Piezoresponse (PFM) and magnetic force (MFM) modes of scanning probe microscopy (SPM) were utilised to assess responses from piezoelectric and magnetic grains. Localised piezoelectric hysteresis loops were measured on KNN grains in composites made by all four methods. Typical hard magnetic hysteresis loops for BaM were observed exhibiting high coercivity values (up to 281 kA m−1 or 3530 Oe), and those composites made using solid state reaction and citrate combustion methods, which contained no impurity phases, had close to maximum magnetisation values (equivalent to ~70 A m2 kg−1 for the BaM phase). SEM, MFM and magnetisation measurements all suggested that the grain size of the BaM in the composites made using solid state reaction, co-precipitation and citrate combustion methods was around 1 µm, and consisting of single magnetic domains. As a result, it is likely that these samples will exhibit a high degree of magnetoelectric coupling.

Heterogeneities and material-scales providing physically-based damping to replace Rayleigh damping for any structure size

This study is aimed to develop a damping model to accurately predict vibration amplitude reduction for any size of structure. It is developed in the framework of multi-scale analysis, where different sources of energy dissipation at captured at material-scales (e.g., scale of representative volume element). In particular, we illustrate details for concrete structures, where one needs different failure mechanisms like plasticity, damage and viscosity to represent different sources of dissipation are reproduce the typical hysteresis loops of concrete with both residual deformation and change of initial elastic response. The final step in proposed approach is to account for structure heterogeneities by allowing for variability of elasticity limit, which produces the same exponential (rather than linear decay) of vibration amplitudes, just as in the case of Rayleigh damping. However, contrary to Rayleigh damping calibration that can be done only on a single structure (and for a chosen frequency), the proposed approach can be adapted to any structure size and full interval of frequencies of interest. The price to pay is in terms of nonlinear analysis, which is here rendered very efficient by hybrid-stress formulation to uncouple different damage mechanisms and by using linear evolution equations for internal variables representing such mechanisms. The details illustrated for 1D and 3D concrete model can be easily adapted to other materials, such as steel, soils etc.

Microstructure and electrical property of NaNbO3 ceramics prepared by cold sintering process assisted post-heat-treatment

NaNbO3 (NN) ceramics have attracted worldwide attention as a kind of dielectric material, but with the drawbacks of difficulty in sintering. In this work, high performance NN ceramics were achieved by using cold sintering process assisted post-heat-treatment (CSP-PHT). The effects of cold sintering process (CSP) and post-heat-treatment (PHT) of NN ceramics on the microstructure and electrical properties were systematically investigated. High dense NN ceramics with relative density of 92.6% were achieved by CSP, which increased to 96.9% with improved crystallinity after PHT at 1230 °C. Of particular interest is that the NN ceramics prepared by CSP-PHT exhibited typical ferroelectric hysteresis loops with large polarization of 34.2 μC/cm2, which is much higher than the conventional sintering (CS) method at 1300 °C with value of 24.8 μC/cm2. Our work shows that CSP-PHT is an effective method to obtain high-performance NN ceramics at lower sintering temperature.

Polarization switching in Bi0.8La0.2FeO3 films with ferroelectric/semiconductor heterojunctions

Bi0.8La0.2FeO3 (BLFO) films are deposited directly on low-resistance Si (100) substrates by the pulsed laser deposition method. Compared with the typical hysteresis loops of ferroelectric films, those of the BLFO/Si samples, with almost horizontal upper and lower ends, severely shrink in the center part, and the coercive voltage is extremely small. A systematic analysis of the dielectric and ferroelectric characteristics reveals that a p–n junction forms between BLFO and Si, with oxygen vacancies accumulating near the interface. The polarization switching is accompanied by the change of the interface barrier and the migration of charged defects. This work provides a reference for the direct growth of ferroelectric films on silicon substrates and is of great significance for the development of the silicon-based electronic devices.

Nanochannel‐Based Interfacial Memristor: Electrokinetic Analysis of the Frequency Characteristics

AbstractAs a novel class of memristors, nanochannel‐based interfacial memristors in polydimethylsiloxane offer great flexibility and low cost. With practical attributes of novel transport phenomenon in nanofluidics, analysis of the physical properties and operational mechanisms in such memristor devices is possible. Made of pure soft‐matter materials, this type of device exhibits facile tuning of device conductance via the modification of solution interface positions. Under continuous sweep voltage, a typical hysteresis loop for a memristor can be observed. In this article, the dynamic frequency characteristics of this device is measured, which is regarded as a typical memristor characteristic as previously predicted. However, the physical mechanism behind such memristive behaviors and frequency characteristics is seldomly reported. Generalizing conventional physical models, here a comprehensive model including continuous voltage changes and surface tension modifications is proposed, which is able to predict the interface position changes and explain the conductance switching and frequency property experimentally observed in the device. Provided with a probable explanation of the physical mechanism behind this class of device, the model can serve as a candidate method in designing new nanochannel‐based structures or materials, aiming at more novel functionalities in neuromorphic computation.

AgNbO3 antiferroelectric film with high energy storage performance

Antiferroelectric materials with double hysteresis loops are attractive for energy storage applications, which are becoming increasingly important for power electronics nowadays. Among them, AgNbO3 based lead-free ceramics have attracted intensive interest as one of promising environmental-friendly candidates. However, most of the AgNbO3 based ceramics suffers from low dielectric breakdown strength (Eb). The limitation of low Eb is broken to some extent in this work. Here, AgNbO3 epitaxial films were fabricated by pulsed laser deposition, which possess high Eb of 624 kV/cm. The (001)AgNbO3 epitaxial film reveals typical antiferroelectric hysteresis loops when the applied electric fields are over 300 kV/cm. A recoverable energy density of 5.8 J/cm3 and an energy efficiency of 55.8% are obtained at 600 kV/cm, which demonstrates the great promise of the AgNbO3 film for energy storage applications.

Analysis of hysteresis rule of energy-saving block and invisible multi-ribbed frame composite wall

The energy-saving block and invisible multi-ribbed frame composite wall (EBIMFCW) is a new type of load-bearing wall. The study of this paper focus on it is hysteresis rule under horizontal cyclic loading. Firstly, based on the experimental data of the twelve specimens under horizontal cyclic loading, the influence of two important parameters of axial compression ratio and shear-span ratio on the restoring force model was analyzed. Secondly, a tetra-linear restoring force model considering four feature points and the degradation law of unloading stiffness was established by combining theoretical analysis and regression analysis of experimental data, and the theoretical formula of the peak load of the EBIMFCW was derived. Finally, the hysteretic path of the restoring force model was determined by analyzing the hysteresis characteristics of the typical hysteresis loop. The results show that the curves calculated by the tetra-linear restoring force model in this paper agree well with the experimental curves, especially the calculated values of the peak load of the wall are very close to the experimental values, which can provide a reference for the elastic-plastic analysis of the EBIMFCW.