Hysteresis Loop Characteristics Research Articles

Modeling in Software Environments for the Study of the Physical Properties of Ferromagnets

The work is devoted to the study of the properties of ferromagnets in different software environment. The use of magnetic properties of substances is based on whole sections of technology, such as magnetic recording of sound and images, magnetic flaw detection, magnetic exploration of minerals. There are various types of magnetic materials, among which ferromagnets have the most practical application. They are used as cores in transformers, generators, electric motors and other devices. The study of magnetic properties can be carried out both by hardware methods of direct measurements and by simulation. Traditionally, modeling of properties of both bulk and film structures is performed using statistical Monte Carlo numerical methods. At the moment, it is possible to make correlations between the crystalline structure of a magnetic material, the intensity of a ferromagnet, and the change in magnetic properties, such as the coefficient of magnetic resistance. The presented work demonstrates a method of studying the properties of ferromagnets using simulation in the software environments Proteus Professional Demonstration and MULTISIMTM for EDUCATION. The features of these software environments are analyzed. The simulation is performed by constructing in the software environments a circuit with a transformer and an oscilloscope, which determines the characteristics of hysteresis loops. To study the magnetic properties, we proposed a circuit, which includes resistors R0, R1, R1, capacitor C, ammeter, transformer T, power supply and oscilloscope outputs. The magnetic properties of the ferromagnetic material were investigated by analyzing hysteresis loops in a 500 Hz magnetized field using an electron beam oscilloscope. The studied ferromagnet in the form of a toroid has a magnetizing (primary) and measuring (secondary) windings, the number of turns of which influence on the final results of the shape of hysteresis loop. It is shown how the transformer parameters and circuit components affect the appearance of the hysteresis loop. The characteristics of hysteresis loops and their relationship with the properties of the ferromagnet are analyzed. The paper presents the instruction for hysteresis loops observation on the oscilloscope. Methods of measurements, equestions, and calculations of magnetic characteristics are presented: coercive force, residual induction, magnetic permeability, magnetization. The features of modeling in each software environment are analyzed.

A micromechanical tension-compression fatigue hysteresis loops model of fiber-reinforced ceramic-matrix composites

In this paper, a micromechanical tension-compression fatigue hysteresis loops model of fiber-reinforced ceramic-matrix composites (CMCs) is developed. Upon unloading or reloading, the stress-strain of tension-compression fatigue hysteresis loops are divided into three different regions. Multiple micromechanical damage parameters of unloading transition stress, closure stress of the matrix cracking, compressive transition stress, complete compressive stress, and reloading transition stress are adopted to characterize the tension-compression stress-strain hysteresis loops. The characteristics of the tension-compression fatigue hysteresis loops of unidirectional SiC/CAS composite are analyzed for different material properties, damage stage, tensile fatigue peak stress, and compression fatigue valley stress. The experimental tension-tension and tension-compression fatigue stress-strain hysteresis loops of unidirectional SiC/CAS composite are predicted using the developed micromechanical models. Under low fatigue valley compressive stress, the tension-compression fatigue hysteresis loop exhibits no closure of matrix cracking; and under high fatigue valley compressive stress, the tension-compression fatigue hysteresis loops exhibit closure of matrix cracking, and complete compressive in the fiber and the matrix. However, the compressive valley stress has no effect on the values of matrix cracking closure stress, compressive transition stress, and complete compressive stress.

Hysteresis modeling and compensation of a pneumatic end-effector based on Gaussian process regression

This paper proposes a data-driven statistical learning method to identify the force-pressure hysteresis of a pneumatic end-effector based on Gaussian process regression (GPR). Given the actual complex characteristics of the hysteresis phenomena, GPR is used to establish the relationship between the input and output variables of the hysteresis as a first-order nonlinear differential equation ignoring the high-order dynamics without specifying any hyperparameters or considering the special features of hysteresis loops. The inverse hysteresis model can be derived directly. The parameters of the GPR are determined by choosing low-frequency triangle-wave pressure excitations as the training set, and then the prediction performance of the present model is tested under different types, amplitudes, and period conditions of pressure signals as the verification sets. Compared with two types of modified Prandtl-Ishlinskii model, the proposed model achieves better accuracy in both training and verification sets. Based on the inverse hysteresis feedforward compensator, comparative experiments of the force-tracking control are conducted in the form of the open-loop and closed-loop controllers, of which the results indicate the effectiveness and superiority of the proposed model.

Dynamic magnetic hysteresis loop features of molecular-based magnetic materials and ferrimagnetic systems by the path probability method

Dynamic magnetic hysteresis loops (DMHL) features of molecular-based magnetic materials and ferrimagnetic systems are investigated by a mixed spin (1/2, 1) model by means of the path probability method (PPM). The PPM contains two rate constants; hence the DMHL features have been studied by using the method with two rate constants. In particular, the effects of the repulsive (J<0) and attractive (J>0) bilinear nearest-neighbor pair interactions, temperature (T), crystal-field interaction (D), angular frequency (ω) of the oscillating magnetic field and especially the rate constant (k2), which corresponds to the wheel speed in the melt spinning technique (MST), on the DMHL are investigated. The shapes and areas of hysteresis loops are affective sensibility by these system parameters. We also investigate the magnetic coercive fields and remanents magnetizations as a function ω. We found that the most of our results are in a good agreement with some theoretical and experimental reported works. We also observe the novel and interesting DMHL behaviors for lower values of T, and higher values of ω, k2 and D.

Structural and magnetic behavior of CTAB assisted BiFeO3 by self-combustion route

Abstract With a large number of published articles, Bismuth ferrite (BiFeO3, BFO) is one of the most studied multiferroic materials, and offers the great possibilities for industrial and technological applications. The prime motivation to conduct the present research is: BFO has poor magnetic behavior due to the wide difference between its Neel and Curie temperature, at bulk scale. Herein, we report the enhanced magnetic properties of BFO, by an interplay of structure assisting agent, CTAB. A facile synthesis route, sol–gel autocombustion method was adopted to materialise the multiferroic BFO product. The obtained BFOs (pristine as well as CTAB assisted BFO), were analyzed using XRD, SEM, and VSM. As developed BFOs showed rhombohedral crystal structure having space group R3c, with some impurity phases. The morphological analysis of BFOs displayed agglomerates of small particles having an irregular shape and size, which are typical in autocombustion synthesis route. At room temperature, both BFOs (pristine and CTAB assisted BFO) exhibited the characteristic magnetic hysteresis loop which confirms the ferromagnetic nature. It was observed that CTAB played an important role in an enhancement of magnetic properties (saturation magnetization (Ms), remanence (Mr) and coercivity (Hc)). Therefore, the obtained synthetic protocol of developing BFO using CTAB have a great potential in view of improved magnetic properties of BFO material based applications.

Hysteresis response of nonlinear flutter of a truss girder: Experimental investigations and theoretical predictions

Nonlinear flutter response with hysteresis loop characteristics is a special aerodynamic instability phenomenon, and is of great importance and of practical interest to long span bridge designs. This paper presents a comprehensive study on nonlinear flutter of a bridge deck that has hysteresis loop characteristics over a range of wind speeds close to the flutter onset speed, using a section model wind tunnel test and theoretical analyses. The evolutions of the hysteresis loop in both the single degree of freedom (SDOF) system in torsion and the 2 degrees of freedom (2DOF) system in the vertical direction and in torsion are studied. The formation mechanism of the hysteresis loop is discussed using the equivalent total damping as a function of vibration amplitude. Two nonlinear mathematical models for the SDOF and the 2DOF systems are proposed to predict the nonlinear flutter responses, in which both the structural and aerodynamic damping are expressed as functions of time-varying displacements. An approach is proposed to identify the aerodynamic parameters based on the displacement time histories using a harmonic balancing technique. Using the identified aerodynamic parameters, a distinct dynamic system with the same section was used to validate the accuracy of the proposed models.

Cupper doping effect on the electrical characteristics of TiO2 based Memristor

Nanostructures as a starting point to solve the scaling problems of the CMOS technologies, have been concerned the attention of numerous researchers. By strong demanding for nonvolatile memory technology, resistive memories based on metal oxide has been common due to several advantages, such as low-power consumption, good scalability and fast switching speed. Even though high-temperature fabrication process has a large area limitation by their material characteristics. Metal oxide thin films are respectable candidate to fabricate at nano scale solid state electronic device. Metal/Metal-Oxide/Metal structure is employed to several devices such as Non-volatile able memories, RRAMs, resistance switching based devices and memristor. The foundation of the primary TiO2 based memristor served a number of consequences for understanding the conduction mechanisms during the formation of hysteresis loop. Also, the current-voltage characteristics (hysteretic loop) which is formed by mobile anions or oxygen vacancies motion in the set and reset process, is clarified the resistive switching behavior by swapping the resistance of TiO2 thin film. Here, the effect of Cu doping into TiO2 based memristor by focused on the hysteresis loop characteristics is considered. Similarities of hysteresis loop form in Cu doped devices are explored. Hysteresis loop is symmetric for structures having pure TiO2; however, asymmetric character appears after Cu doping. After the formation process hysteresis loop of the Cu doped devices shown higher conductance path on (I-V) characteristic than the initial forming process loop in positive cycle loop as the un-doped TiO2. Also, in spite of un-doped TiO2, this (I-V) hysteresis loop character shown lower path conductance than primary forming process in the negative cycle loop. Surface roughness of 30nm thick TiO2 is increased from 0.3nm to 0.77nm as Cu doping increased from %10 to %30. Unfortunately, XRD results cleared that there is no exchange in crystallinity but optical band gap decreased as Cu doping increased.

Vacancy-induced resistive switching and synaptic behavior in flexible BST@Cf memristor crossbars

In this study, carbon fibers (Cf) coated with Ba0.6Sr0.4TiO3 (BST) (BST@Cf) were prepared by magnetron sputtering and subsequently heated in nitrogen to produce oxygen vacancies. BST@Cf and nitrogen-treated BST@Cf were cross-stacked on polyimide (PI) film to make a BST@Cf memristor. The electrical properties of BST@Cf memristor were measured after being bent 3000 times. The device exhibits bipolar figure-of-eight (f8) hysteresis loop characteristics under applied voltage. The hysteresis loops narrow with increasing temperature of heat treatment in nitrogen, due to decrease in oxygen vacancy concentration. The hysteresis loops demonstrate the switching process of resistance between high resistance state (HRS) and low resistance state (LRS), with a maximum HRS/LRS ratio of 106. The switching process can be divided into two parts, corresponding to Schottky Emission and Fowler-Nordheim (F–N) Tunneling. It is notable that no electroforming voltage is required to stimulate the memristor. The constructed memristor was cycled successfully 1000 times and retained the LRS 787 s during power cut off. In addition, the device exhibited synaptic behavior including learning and forgetting processes, in accordance with the paired-pulse facilitation (PPF) rule. The use of BST@Cf in the construction of the nonvolatile memristor imparts flexibility to the device allowing for the possibility of wearable flexible intelligent memristor based electronic devices in the future.

Suspended sediment budget and intra-event sediment dynamics of a small glaciated mountainous catchment in the Northern Caucasus

The sediment dynamics of (peri-)glacial catchments can be highly variable and complex. Understanding these dynamics and their underlying causes is not only of interest from a scientific perspective but also required to address the practical problems with which they are often associated. In order to better understand the sediment dynamics of glaciated mountainous catchments, suspended sediment fluxes in the 9.1 km2 Djankuat catchment (North Caucasus, Russia) were monitored intensively during the 2017 ablation season. The intra-event suspended sediment dynamics were studied using a newly proposed simple hysteresis index (SHI), quantifying to what extent evolutions in sediment concentration are characterized by a clockwise or anticlockwise hysteresis loop. The resulting catchment suspended sediment yield was 1033 t km−2 year−1, with the glacier itself contributing 72% of the suspended sediment load. However, during rainfall events, also hillslope erosion in the proglacial area became a very significant sediment source. Clockwise hysteresis loops occurred in 61.8% of the events, while anticlockwise in 11.8%. On the other hand, only 47.8% of the total suspended sediment flux was transported during clockwise events. Our observations clearly indicate that events showing a stronger clockwise pattern (i.e., a higher SHI) are associated with a larger sediment input from the proglacial area. Overall, our results provide data and insights on sediment dynamics in an understudied environment. They illustrate that the type and characteristics of sediment concentration hysteresis loops are to some extent linked to the dominant sediment sources during the event. As such, the proposed methodology and SHI may also help with a better understanding of sediment dynamics in other environments.

Evaluation of lacustrine mudstone top sealing capacity in the Lenghu-5 area, Qaidam Basin, Tibetan Plateau

Top seal capacity is one of the fundamental geological factors that must be considered during petroleum exploration. Based on thin section, low-pressure N2 adsorption, bulk mineralogy, X-ray diffraction (XRD), mercury injection experiment and pressure data, the sealing capacity, lithofacies, petrophysics, diagenesis, capillary breakthrough pressure, overpressure, and brittleness index characteristics of a lacustrine mudstone top seal from the Lenghu-5 area, Qaidam Basin, Tibetan Plateau was investigated. The bulk rock composition of the top seal was dominated by clay minerals with carbonate cements and has a gross mudstone to sandy mudstone lithofacies. The isotherms from low-pressure nitrogen adsorption tests which presents as reversed S-shaped, belong to type B and the characteristics of hysteresis loops indicating the silt-like pores in the samples. The pores of the mudstone top seals are predominantly mesopores according to the N2 adsorption and mercury injection experiment results. The cumulative mudstone thickness varies from 100 to 1400 m. The overpressured mudstone top seal in the Lenghu-5 area has three potential hydrocarbon preservation implications: overpressure cannot seal oil and gas, overpressure seals oil and gas directly, and overpressure seals oil and gas indirectly. The brittleness index (BI) values calculated by four methods based on the mineralogical composition of the mudstone top seals and the BI is higher at the top and bottom of the studied interval than in the middle mudstone layer. Based on the mud content, pore diameter, thickness, diagenetic stage, capillary breakthrough pressure, overpressure coefficient and brittleness index of the lacustrine mudstone, the top seal in the Lenghu-5 area is classified into four types: type I, II, III and IV, representing good to poor sealing capacities. The method for evaluation of the sealing capacity in this study can not only provide useful guidance for hydrocarbon exploration in Lenghu-5 area, Qaidam Basin, but also can be used in basins around the world by selecting the main influencing factors of sealing capacity in the basin.

Modeling and Performances of the Orthogonal Fluxgate Sensor Operated in Fundamental Mode

Fluxgate magnetometer is an important device for weak magnetic-field measurements. By adding a large dc bias excitation current, the performances of fluxgate can be highly improved. In this article, based on the assumption of the single-domain state within the probe core wire, the quasi-static Stoner–Wohlfarth model (SW model) was used to construct a mathematic model for the output signal of the orthogonal fluxgate probe operated in fundamental mode (FM-OFG). The dynamic hysteresis loop characteristics were also considered here, and the expected first-harmonic output signal corresponding to the theoretical analysis was obtained from our model. A prototype FM-OFG probe was fabricated by using a 20 mm-long Co–Fe–Nb–Si–B amorphous microwire as core wire and a 1500-turn solenoid as pickup coils. Output performances were analyzed at different external fields, ac excitation currents, and dc bias currents. A good agreement between the modeling results and the experimental ones was found. The noise level was reduced down to 9.01 pT/rt (Hz).@.1 Hz. The simulation method and experiment results provide theoretical guidance for the subsequent design and improvement of the FM-OFG.

Characterisation of welded plate through micro-magnetic technique

Characterisation of the welded plate by Non-destructive testing technique are gaining more popularity over destructive testing. In this study, the variation in the hysteresis loop behaviour were examined with the variation of magnetic field intensity on the base metal, heat affected zone and weld metal regions of gas metal arc welded ferritic stainless steel plate. The behaviour of hysteresis loop characteristics such as average permeability, remanence and coercivity have been investigated and it was found that these characteristics depend upon the grain size and microhardness as well as magnetic field intensity. Coercivity of each region vary in proportion with the variation of magnetic field intensity and inversely proportional to the grain size, but the variation of other hysteresis loop characteristics with the magnetic field intensity in each region is irregular.

Magnetic hysteresis loop behaviour of welded ferritic stainless steel 409L with the variation of magnetic field intensity

Hysteresis loop analysis technique, being a non-destructive testing technique is more beneficial than the destructive testing techniques to characterise the welded plate. In this study, the ferritic stainless steel AISI 409L plate was butt welded by gas metal arc welding process. Hysteresis loop analysis technique was used to study the microstructures and microhardness of the base metal region, heat affected zone and weldmetal zone. This study has been carried out at four different values of magnetic field intensity 250, 500, 750 and 1000 Oe. The effect of variation of magnetic field intensity on the hysteresis loop characteristics (average maximum flux density and core loss) has been investigated for base metal, heat affected zone and weldmetal zone. It was found that for each region, the average maximum flux density as well as core loss increases on increasing magnetic field intensity. Also, the variation of average maximum flux density is inversely proportional to the microhardness of the region at each value of magnetic field intensity.

Magnetostatic properties of assembly of magnetic vortices

The ultrasonic oscillation of a macroscopic sample in a viscous liquid is used to create magnetic particles of FeCo alloy with an average diameter D ~100 nm. The FeCo particles obtained have a high specific saturation magnetization, Ms = 1960 emu/cm3, close to that of a bulk sample. The hysteresis loop of a magneto-polymer composite prepared from FeCo particles shows low coercive force and a remanent magnetization close to zero. The magnetic saturation of the magnetic composite samples is achieved in a sufficiently strong magnetic field, H = 6.5 kOe. The hysteresis loop features of the magnetic composite have been explained by means of the numerical simulation of the quasistatic hysteresis loops of non-oriented dilute assemblies of spheroidal FeCo particles with various aspect ratios.

Analysis on nonlinearity of antiferroelectric multilayer ceramic capacitor (MLCC) for energy storage

The nonlinearity of a commercial antiferroelectric (AFE) multilayer ceramic capacitor (MLCC) was investigated via hysteresis loop and DC bias characteristics. Capacitors based on linear polypropylene and relaxor ferroelectric with similar initial capacitance were chosen for comparison. Higher stored charge and energy can be achieved in AFE capacitor due to its nonlinear polarization behavior. In addition, the discharge current of AFE capacitor increases nonlinearly, resulting in higher discharge current. The special energy storage and discharge behaviors are explained physically by the electric-field-induced phase transition. This work indicates that AFE dielectrics are very promising for applications in power electronics and pulsed power.

Material characterization of friction stir welded IS-2062 steel plate by hysteresis loop analysis

Present study attempts to characterize the IS-2062 of grade B steel after performing the friction stir welding. Welded steel plates have been characterized with the hysteresis loop characteristics at various magnetizing frequencies with different waveforms. Results obtained from hysteresis loop analysis were correlated with the microhardness measurement and metallographic study of welded samples. A comparison between base metal and welded sample was carried to assess the changes occurring in hysteresis loop characteristics owing to changes in mechanical properties upon friction stir welding. The grain size was observed to decrease upon friction stir welding, resulting in a greater microhardness in weld sample when compared with the base metal. Variation in magnetic hysteresis loop response like Coercivity, Permeability, Remanence and Core loss were correlating well with the grain refinement and changes in microhardness resulting from friction stir welding of steel. The study would help to establish the micro-magnetic analysis as a nondestructive technique for characterization of friction stir welded steel.

In Ukrainian

The effect of the surface modification of fumed silica (SiO 2 ) with poly(dimethylsiloxane) (PDMS) on the rheological properties of its suspensions in vaseline oil has been studied in the current work. The composites with different polymer content (from 5 to 40 wt. %) were synthesized by using the method of liquid phase adsorption modification of silica with linear PDMS-1000 (molecular weight W m ≈ 7960, degree of polymerization d p = 105). It is shown that the structural and morphological characteristics of SiO 2 /PDMS composites are significantly different from those for the initial silica, and depend on the concentration of PDMS. In particular, the specific surface area of the composites, determined by the method of low-temperature desorption of argon, is inversely correlated with the content of polymer. The morphology of SiO 2 /PDMS composites and aggregation of primary particles of fumed silica strongly depends on the method of liquid phase adsorption modification: the initial fumed SiO 2 has a wider distribution of aggregates in size than that in polymer composites according to AFM data. Suspensions with a solid phase concentration (SiO 2 /PDMS) of 5 wt. % in a lyophilic dispersion medium (vaseline oil) demonstrate typical thixotropic behavior with a characteristic hysteresis loop on the rheogram, corresponding to increasing the destruction of the dispersion structure while stepwise shear rate increment and partial its restoration while subsequent stepwise shear rate decrement. Both the effective viscosity values corresponding to the maximum destruction of the suspension structure obtained at high shear rates and the effective viscosity values corresponding to partial restoration of the structure in the subsequent stepwise shear rate decrement mode decrease with increasing polymer content in the studied composites. However, it has been found that the initial values of the effective viscosity for the studied dispersions with a practically almost intact structure (at the lowest shear rates) are higher for dispersions of SiO 2 /PDMS composites with a low concentration of PDMS 10–20 wt. % compared with similar suspensions of the initial silica. A correlation between the effective viscosity and the specific surface area of composites is shown.

Estimation of material properties using hysteresis loop analysis in friction stir welded steel plate

Material properties of IS 2062 steel plates after friction stir welding has been characterized by hysteresis loop characteristics at three different frequency range; low frequency, medium frequency and high frequency range. Magnetic field was applied with sinusoidal waveform and triangular waveform over base metal and friction stir welded sample for comparative analysis. Rectangular sample of 3 mm thickness were welded using tungsten carbide tool having 15 mm shoulder diameter at 800 RPM and 150 mm/min welding speed. Micro-hardness testing and metallographic study of welded samples were also performed to study the effect of change in material properties on magnetic response of material. Grain refinement upon friction stir welding changed the microhardness of weld nugget. Depth of penetration of external magnetic field at three different frequencies ranges not only changed the shape of hysteresis loop but also resulted into wide variation in hysteresis loop characteristics such as permeability, remanence, average maximum flux density and core loss.

Electrical properties and defect compensation mechanism of B-site Cu2+ substituted K0.5Na0.5NbO3 ceramics

Cu2+ substituted K0.5Na0.5NbO3 ceramics at B-site K0.5Na0.5(Nb1−xCux)O3−3x/2 (KNNC) were prepared by a solid state method. The dielectric, ferroelectric properties and defect compensation mechanism were studied. With the concentration of Cu2+ increasing from 0.005 to 0.10, permittivity and dielectric loss decrease, but further increasing the concentration of Cu2+ increasing leads to the increment of permittivity and dielectric loss. All KNNC ceramics exhibit double hysteresis loop characteristics. When the doping concentration Cu2+ is low (x = 0.0075), the double hysteresis loop disappears at large electric field, nonetheless, when x = 0.015, it maintains the characteristics of the double hysteresis loop even under the high electric field. The corresponding mechanism is explained from the aspects of correlation between defect dipoles and polarization orientation.

Synthesis and characterization of Co1–2xNixMnxCeyFe2–yO4 nanoparticles

Spinel ferrite Co1–2xNixMnxFe2–yCeyO4 (0.0 ≤ x = y ≤ 0.3) nanoparticles (NPs) were prepared by sol-gel auto-combustion method. The synthesized NPs were examined using several techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) coupled with EDX and elemental mapping, transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and a vibrating sample magnetometer (VSM). The analysis of the crystal structure and the phase identification of samples indicates the formation of spinel cubic phase with the occurrence of CeO2 as secondary phase when the content of Ce substitution element increases. In addition, all produced samples exhibit cubic symmetry with space group Fd3m. TEM confirms the presence of two phases, i.e., the cubic spinel ferrite and the cubic cerium oxide (CeO2). The characteristics of hysteresis loops reveal the soft ferrimagnetic nature of the different synthesized samples. The saturation (Ms) and remanent (Mr) magnetizations fall on increasing the content of substituting elements. Compared with pure CoFe2O4 NPs, the value of coercive field (Hc) slightly increases for x = y = 0.1 and x = y = 0.2 NPs. Then, Hc reduces with further increasing the x and y contents. The squareness ratio is found to be in the 0.528–0.400 interval, indicating the single domain NPs with uniaxial anisotropy for the different produced NPs. The magneto crystalline anisotropy constant (Keff), anisotropy field (Ha), magneton number (nB) and the demagnetizing field (N) were also determined and discussed.