EXPERIMENT EM1 MAGNETIC INDUCTION AND FERROMAGNETIC HYSTERESIS

2015

Learning the formation of the hysteresis loop can help students to understand the ferromagnetic properties of materials. Also, studying the hysteresis loop gives a brief idea about the relationship between the magnetic flux density B, magnetic field strength H and magnetization M. In the present study, a model experiment is presented which was prepared for learning the fundamentals of the hysteresis loop. The results of this easy and instructive experiment are substantially compatible with theoretical knowledge.

Le Journal de Physique IV, 1997

A new method of obtaining physical information about a system of fme fenite powder, from the hysteresis experienced by a ferromagnetic core as it dissipates energy in an RLC circuit is presented. The models of the magnetization processes are classified in three categories: physical, phenomenological and mixed. Hodgdon developed a purely mathematical model that was tested on magnetization processes in magnetic cores. The values of the model's parameters are calculated l?om experimental data obtained in a series RLC circuit. The capacitor discharges through the circuit and the core performs a complex magnetization process. The voltage across the capacitor and the current intensity are measured. These magnetization pmcesses could be also simulated with a mixed-type model. The identification methodology of the mixed model requires the measurement of some magnetization curves: the first magnetization curve, the major hysteresis loop, the isothermal remanent magnetization process and the d.c. demagnetization process. In order to preserve the simplicity of the experimental data measurement and to perform the identification of the mixed model, some of the experimental curves required by the identification methodology were simulated with the Hodgdon model. Experiments were performed on soft MnZn fenite core. The results of the identification are discussed.

2008 International Conference on Computer Engineering & Systems, 2008

Effect of the dynamic magnetic hysteresis on the induced currents is investigated. The method used combines a finite element simulation and a dynamic hysteresis modeling. In this paper, we present a numerical procedure capable of analyzing dynamic hysteresis in axial-symmetric problems. The ferromagnetic hysteresis is described by Jiles-Atherton model. This model is integrated in finite element method (FEM) in order to resolve magneto-dynamic problems. The interface between the Jiles-Atherton model and the finite element magnetic vector potential formulation is introduced through the fixed-point iterative technique.

A theory of the hysteresis loop in ferromagnets controlled by the domain wall motion is presented. Domain walls are considered as plane or linear interfaces moving in a random medium under the action of the external ac magnetic field H = H0 sin ωt. We introduce important characteristics of the hysteresis loop, such as dynamic threshold fields, reversal field etc. together with well known characteristics as coercive field and hysteresis loop area (HLA) A. We show that all these characteristics are regulated by two dimensionless combinations of the H0 and ω and intrinsic characteristics of the ferromagnet. The moving domain wall can create magnetic bubbles playing the role of pre-existing nuclei of the reversed magnetization. We discuss a simple model of this process. For magnetization reversal determined by domain inflation we predict that HLA scales as A ∝ ω β H α 0 with α = 1/2 and β = 1/2. Numerical simulations confirm this result.

IEEE Transactions on Magnetics, 1989

A major purpose of the Technical Information Center is to provide the broadest dissemination possible of information contained in DOE's Research and K)eveloprnent Reports to business, industry, the academic community, and federal, state and local governments. Although a small portion of this report is not reproducible, it is being made available to expedite the availability of information on the research discussed herein.

Journal of Materials Processing Technology, 2007

This paper presents a method based on use of a measurement system in order to significantly reduce the time taken and to improve the accuracy in evaluating parameters of the Jiles-Atherton's model of magnetic hysteresis. The steps of the proposed method: (a) data acquisition from the experimental hysteresis loop of the magnetic material under test, (b) evaluation of the model's parameters. In order to highlight the method's effectiveness, the results of experimental tests are also given.

Physical Review B, 1999

We consider three mechanisms of hysteresis phenomena in alternating magnetic field: the domain wall motion in a random medium, the nucleation and the retardation of magnetization due to slow (critical) fluctuations. We construct quantitative theory for all these processes. The hysteresis is characterized by two dynamic threshold fields, by coercive field and by the so-called reversal field. Their ratios to the static threshold field is shown to be function of two dimensionless variables constituted from the frequency and amplitude of the ac field as well as from some characteristics of the magnet. The area and the shape of the hysteresis loop are found. We consider different limiting cases in which power dependencies are valid. Numerical simulations show the domain wall formation and propagation and confirm the main theoretical predictions. Theory is compared with available experimental data. 75.70.Ak,75.60.Ej, 75.60.Ch

IEEE Transactions on Instrumentation and Measurement, 1994

Many methods have been proposed for the determination of the hysteresis loops of magnetic materials, and many mathematical approaches have been proposed to find a good model for the hysteresis phenomenon. However, very few attempts have been made to determine the parameters of the hysteresis model experimentally. This paper will show how, starting from a digital method for the experimental determination of the hysteresis loop under different maximum induction values, the parameters of a hysteresis model can be automatically estimated with good accuracy.

This paper presents an experimental research on magnetic hysteresis loops of a toroidal ferromagnetic core made of electrical steel. The results of measurement of induced voltage, magnetic induction and hysteresis loop are presented. The influence of the frequency and waveform of the excitation magnetic field on the hysteresis loop shape and harmonic content of the induced voltage is analysed and discussed. The presence and variation of higher harmonics content with frequency is correlated with the magnetic domain walls damping mechanism.

IEEE Transactions on Magnetics, 2000