Dynamic Hysteresis Properties Research Articles

A micromagnetic study of sample size effects on dynamic hysteresis properties and dynamic phase transitions of Fe and $$Fe_3O_4$$ nanodisks

A micromagnetic study of sample size effects on dynamic hysteresis properties and dynamic phase transitions of Fe and $$Fe_3O_4$$ nanodisks

Dynamic J-A model improved by waveform scale parameters and R-L type fractional derivatives

PurposeThe purpose of this study is to model the global dynamic hysteresis properties with an improved Jiles–Atherton (J-A) model through a unified set of parameters.Design/methodology/approachFirst, the waveform scaling parameters β, λk and λc are used to improve the calculation accuracy of hysteresis loops at low magnetic flux density. Second, the Riemann–Liouville (R-L) type fractional derivatives technique is applied to modified static inverse J-A model to compute the dynamic magnetic field considering the skin effect in wideband frequency magnetization conditions.FindingsThe proposed model is identified and verified by modeling the hysteresis loops whose maximum magnetic flux densities vary from 0.3 to 1.4 T up to 800 Hz using B30P105 electrical steel. Compared with the conventional J-A model, the global simulation ability of the proposed dynamic model is much improved.Originality/valueAccurate modeling of the hysteresis properties of electrical steels is essential for analyzing the loss behavior of electrical equipment in finite element analysis (FEA). Nevertheless, the existing inverse Jiles–Atherton (J-A) model can only guarantee the simulation accuracy with higher magnetic flux densities, which cannot guarantee the analysis requirements of considering both low magnetic flux density and high magnetic flux density in FEA. This paper modifies the dynamic J-A model by introducing waveform scaling parameters and the R-L fractional derivative to improve the hysteresis loops’ simulation accuracy from low to high magnetic flux densities with the same set of parameters in a wide frequency range.

Ground State Dynamic Hysteresis Properties of Permalloy Nanodisk with Varying Shapes

Ground State Dynamic Hysteresis Properties of Permalloy Nanodisk with Varying Shapes

Effect of the dipolar interaction on the dynamic hysteresis properties of 2D-nanodisks: out of plane driving field case

We have systematically investigated the effect of dipolar interaction strength on the dynamical hysteresis behavior of the in-plane uniaxial anisotropic nanodisk system modeled by the classical Heisenberg model under the effect of the time-dependent external out-of-plane periodic magnetic field. Dynamical hysteresis loops, as well as hysteresis quantities (hysteresis loop area, coercive field, remanent magnetization), have been examined both in-plane and out-of-plane magnetization components by means of Monte Carlo simulation based on Metropolis Algorithm. Our simulation results suggest that the response of the in-plane and out-of-plane components of the magnetization have different hysteresis characteristics. For instance, while the out-of-plane component of the magnetization has ordinary dynamically disordered hysteresis curves, bowtie-shaped hysteresis loops have been obtained for the in-plane component of the magnetization. Disappeared dynamical order has been observed with the rising strength of the dipolar interaction.

Influences of the interaction parameters on the dynamic hysteresis of a mixed spin (1/2, 3/2) Ising model under the presence of an oscillating magnetic field

Within the path probability method, the influences of the interaction parameters on the dynamic hysteresis properties of a mixed spin (1/2, 3/2) Ising model driven by a time-varying magnetic field were investigated. First, we examined the effects of the interaction parameters, namely temperature, angular frequency, the rate constant and the exchange interactions on the dynamic hysteresis loops. Then, we investigated the impacts of the interaction parameters on the dynamic coercive fields and dynamic remanent magnetizations. Some of obtained results are in, qualitatively, good agreement with some theoretically reported studies as well as experimental works in some magnetic materials and the hysteresis loops obtained within the melt spinning method.

Dynamic hysteresis modeling for soft magnetic composites based on isotropic vector play model and Cauer ladder network

PurposeThis paper aims to propose an effective modeling method of dynamic hysteresis properties for soft magnetic composite (SMC) core using an equivalent circuit representation. Because the eddy currents flowing inside iron powder particles should be considered, it is well known that an accurate magnetic field analysis of the SMC core in a wide range of excitation frequency is not easy. To overcome this difficulty, a dynamic hysteresis modeling based on the standard Cauer circuit is investigated.Design/methodology/approachIn the proposed method, the first inductance represents the static magnetic property of the SMC, and the latter part represents the dynamic effect because of the eddy currents. The values of the circuit elements were determined by an optimization method based on symmetric loops measured at several frequencies. To verify the validity of the proposed modeling method, finite-element analyses of a ring core inductor and an alternating current reactor were performed.FindingsBy comparing the simulated and measured magnetic properties, the necessity to consider magnetic hysteresis in the equivalent circuit model is clarified. Furthermore, the frequency-dependent inductances of practical reactors can be obtained from the finite-element analysis combined with the proposed method.Originality/valueThis paper demonstrates the significance of determining the circuit parameters in the equivalent circuit for dynamic hysteresis modeling based on the measured magnetic properties. The effectiveness of the proposed method is verified by comparing frequency-dependent inductances of two kinds of reactors between the simulation and measurement.

Modeling of Magnetostrictive Property of Electrical Steel Sheet Under Vectorial Excitation

An accurate estimation for the magnetostrictive effect in an electrical steel sheet is helpful for determining the deformation and noise originating from magnetostriction during the design stages of electric devices. Because of limited measurement conditions, the rotational magnetostrictive modeling has been left aside during the calculations of core deformations. In this paper, the dynamic hysteresis properties of magnetostriction under different elliptic magnetization loci in a grain-oriented electrical steel sheet are investigated based on a rotational magnetic properties tester. A dynamic magnetostrictive model is proposed, in which the principal strains of magnetostrictions are time-dependent on variations of magnetic flux density, and the influences of past magnetization histories of material on the magnetostrictive strains are taken into account. Finally, magnetostrictive characteristics of a single-phase transformer core model built with uncut cores are analyzed and verified by experimental results. The results show that the rotational magnetostriction in the corner area is found to have a major contribution to core vibration and the proposed model can be employed to estimate the rotational magnetostrictions effectively.

Triangular Ising Ferromagnet with Mixed Spins (A = 1/2, B = 1/2, C = 1): Dynamic Magnetic Properties and Hysteresis Curves

The dynamic properties of the triangular Ising ferromagnet consisting of the mixed spins A = 1/2, B = 1/2, and C = 1 is studied by using the mean-field theory (MFT) as well as Glauber-type stochastic dynamics (GSD). The coupling equations to investigate dynamic behaviors of the system are calculated, and phase transitions, phase diagrams, and hysteresis curves are obtained. From these studies, first- and second-order transition lines, the dynamic phase diagrams (DPDs) in the (T,h 0) and (T,d) planes, and single hysteresis curves are presented. In the DPDs, dynamic tricritical point due to the first- and second-order phase transitions are observed. It is found that the dynamic hysteresis properties of the triangular system strongly depend on the temperature and crystal field.

Dynamic Magnetic Hysteresis Properties in a Two-Dimensional Mixed Ising System Designed with Integer and Half-Integer Spins

Dynamic magnetic hysteresis properties in a two-dimensional mixed Ising system designed with integer and half-integer spins, namely spin-1 and spin-5/2, are investigated comprehensively on the basis of the mean-field approximation and the Glauber-type stochastic dynamics, namely dynamic mean-field approximation (DMFA). In particular, we examine the effect of Hamiltonian parameters on dynamic hysteresis properties. As a result of this examination, some characteristic hysteresis behaviors are obtained, such as the existence of single, double and triple hysteresis. Moreover, we study to obtain coercive field and remanent magnetization. Our results are compared with some experimental and theoretical works to find a qualitatively good agreement.

Influence of Frequency on the Kinetic Spin-3/2 Cylindrical Ising Nanowire System in an Oscillating Field

The dynamic phase diagrams depending on the frequency of an oscillating magnetic field and the dynamic hysteresis properties of the kinetic spin-3/2 cylindrical Ising nanowire (CIN) system are studied by means of the mean-field theory based on Glauber-type stochastic dynamics. It is found that the dynamic phase diagrams display a richer dynamic critical behavior for higher values of frequency than for lower values. The effects of the Hamiltonian parameters on the dynamic hysteresis behaviors of the spin-3/2 CIN system are also discussed.

Temperature‐dependent ferroelectric dynamic hysteresis properties of modified PMN–PZT relaxor ceramics

AbstractTemperature‐dependent ferroelectric dynamic hysteresis properties of modified Pb(Mg1/3Nb2/3)O3–Pb(Zr,Ti)O3 (PMN–PZT) ceramics have been investigated in a wide range from 298 to 433 K. Interestingly, it was found that back‐switching polarization Pbc increased while the hysteresis area 〈A 〉, coercive field Ec, saturation polarization Ps, and remnant polarization Pr all decreased linearly with temperature below 398 K (close to the macro–micro domain transition temperature Tnr). A set of simple linear temperature scaling relations was established, which is different from the power‐law scaling relations for soft and hard PZT ceramics. At further increased temperature, double‐loop features appeared and the ferroelectric properties varied nonlinearly due to the reversible macro–micro domain transition in the T > Tnr region. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The Role of Vacancy Defects on the Dynamic Hysteresis Properties of Ferroelectric Thin Films: Monte Carlo Simulation with the DIFFOUR Model

In this work, the effect of random vacancy defects on the electrical properties of ferroelectric thin-films was studied. The Monte Carlo simulation, based on the ferroelectric DIFFOUR model, was performed in the lattice system with free and periodic boundary conditions. The Metropolis algorithm was considered in choosing the proper states under the presence of the electric field. From the results, the hysteresis area at a given field was found to depend on the thickness of thin films and the vacancy defects of system. For instance, in thicker films, the larger hysteresis area was observed, which is resulted from the stronger ferroelectric interaction. On the other hand, the hysteresis area decreases with increasing vacancy concentration, due to the reduction of ferroelectric interaction on the average. To understand the hysteresis behaviors, the scaling exponents of associated parameters in the power law scaling form were considered. The results were discussed and compared with these from literatures.

Monte Carlo Simulation of Ferromagnetic Hysteresis of 3 Dimensional Ising Spins Using Random Walk under Lennard-Jones Potentials

This work aims to investigate the evolution of magnetic behavior under the effect of external magnetic field applied on the itinerant magnetic Ising spins (or the Ising fluid). Monte Carlo and Random Walk methods were used to simulate the Ising spins in a 3-dimensional space, and to examine the dynamic hysteresis properties. Metropolis algorithm was introduced to update spin configurations on the continuous space. By applying an external magnetic field to Ising spins interaction via Lennard-Jones potential, we found a) at the low temperature and frequency ranges the hysteresis loops was ferromagnetic, broad shaped and expanded, and b) at the high temperature range, the hysteresis loop was paramagnetic and reduced. It is proven that properties of the hysteresis of ferro-fluid can be controlled by varying temperature and frequency of theirs magnetic field signals. Hence, this work may be beneficial to the biomedical engineering applications such as cancer therapy.

Finite Size Scaling of Hysteresis Behavior: Monte Carlo Simulation on DIFFOUR Model

In this work, Monte Carlo simulation was used to study the size dependence of the dynamic hysteresis properties of 2 dimensional ferroelectric system. The DIFFOUR model and Metropolis algorithm were used to investigate the size effect on hysteresis properties. From the simulation, it was found that the competition between the electric field parameters and the system size plays a crucial role on the phase-lag between the polarization and the electric field signals, which defines particular hysteresis properties. In describing the hysteresis behavior qualitatively, finite size scaling formalism, in a power law form, was used to predict relations among the field parameters, system size, and hysteresis. The purpose was to establish phenomenological knowledge of how dynamic perturbations affect the hysteresis in finite ferroelectric system. Comparison with related experiments was also discussed.

Comparative studies of dynamic hysteresis responses in hard and soft PZT ceramics

Lead zirconate titanate (PZT) is a ferroelectric material with very interesting and useful dynamic hysteresis properties. Normally, PZT is doped with donors or acceptors to yield better electrical properties. Soft and hard PZT ceramics are respectively donor- and acceptor-doped PZT, which are commercially available and widely employed in various applications. Previous investigations have mainly been focused on the dynamic hysteresis at room temperature and under stress-free condition. However, when used, these ceramics are normally subjected to stress. More importantly, the ambient temperature is usually not at room temperature. Therefore, this study was to investigate dynamic hysteresis behavior of both hard and soft PZT ceramics with varying compressive stress and temperature. The results clearly revealed the influence of external stress and temperature on the dynamic hysteresis of both types of PZT ceramics. Increasing stress and temperature resulted in a decrease of the hysteresis area of the two types of PZT ceramics.

Influence of the Surfaces on the Nucleation Process During the Cholesteric-Nematic Transition

The nucleation phenomenon in short pitch cholesteric liquid crystals (LC), taking place during the relaxation from the electric field-induced cholesteric-nematic (CN) transition, has been investigated for various boundary conditions. The dynamic hysteresis properties have been studied by direct optical methods. For the first time it is shown the strong evidence that the nucleation is not exceptionally a bulk phenomenon and the supporting solid surfaces may act as nucleation sites. It is confirmed also that the nucleation velocity is not a function of the type of molecular alignment at the liquid crystal/solid interface rather than it depends on the uniformity of the surface interactions with liquid crystal molecules. This result is of importance for time scale optimization in modern fast driving schemes for cholesteric LCDs.

Hysteresis modeling and microstructural analysis of soft amorphous alloys

the dynamic Preisach model is applied to the study of Fe-based and Co-based amorphous alloys, characterized by different microstructural conditions. It is shown that all static and dynamic hysteresis properties are correctly predicted by the dynamic Preisach model by associating with each material a structural parameter, λ, which represents the linear dimension of the correlation regions providing coherent magnetization changes. The dependence of this correlation length on annealing treatments is compared with Kerr-effect domain observations and structural data obtained by differential scanning calorimetry. It is found that λ has a role comparable to that of grain size in micro-crystalline alloys. In particular, it is shown that the linear relation holds, H c = H c0 + c/λ, between the static coercive field H c and l/λ, where the slope c depends on the magnetostriction constant of the material and the amount of quenched-in stresses, while the offset H c0 is connected to surface characteristics.

Application of the Preisach model to the calculation of magnetization curves and power losses in ferromagnetic materials

The ability of Preisach-type scalar models to describe static and dynamic hysteresis properties is discussed. Three aspects are addressed in particular: the description of reversible magnetization processes, the characterization of magnetic interactions, and the calculation of dynamic hysteresis loops. Applications of the standard Preisach model and of the moving Preisach model to the description of Henkel plots in recording media and to the prediction of power losses in metallic soft magnetic materials are discussed. >

Dynamic Preisach model interpretation of power losses in rapidly quenched 6.5% SiFe

We present a study of quasi-static and dynamic hysteresis properties in rapidly-quenched 6.5 wt% SiFe ribbons, in the as-cast state and after various annealing treatments. Data are interpreted by static and dynamic Preisach models. The modifications of static loop shapes vs. grain size as well as those of dynamic loop shapes vs. magnetizing frequency are well described by a lorentzian Preisach distribution. Comparison between experiments and model predictions provides an estimate for the size of the correlation regions responsible for dynamic magnetization changes, This size is found to be about one half of the average grain size in samples annealed at 1100/spl deg/C for 1 hour.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>