Interaction effects detected by Fourier analysis of hysteresis loops and initial magnetization curves

1994 ◽  
Vol 30 (2) ◽  
pp. 863-865 ◽  
Author(s):  
J. Geshev ◽  
V. Masheva ◽  
M. Mikhov
Keyword(s):  
Fourier Analysis ◽  
Hysteresis Loops ◽  
Interaction Effects ◽  
Magnetization Curves ◽  
Initial Magnetization

IRREVERSIBLE SUSCEPTIBILITY OF INITIAL MAGNETIZATION CURVES DEFINED BY ENERGY CONSIDERATION

2007 ◽  
Vol 21 (21) ◽  
pp. 3707-3717 ◽  
Author(s):  
G. GOEV ◽  
V. MASHEVA ◽  
M. MIKHOV ◽  
J. GESHEV
Keyword(s):  
Magnetic Field ◽  
Hysteresis Loops ◽  
Model System ◽  
Magnetization Curves ◽  
Maximum Magnetic Field ◽  
Initial Magnetization ◽  
Curve Method ◽  
Energy Consideration ◽  
Minor Hysteresis Loops ◽  
Magnetization Processes

A method for the estimation of reversible and irreversible susceptibilities of initial magnetization curves has been developed. It deals with the energy necessary for magnetizing and demagnetizing the sample, but neither with the nature of the magnetization processes nor with a specific type of anisotropy, so it could be applied for a wide variety of real materials. A set of minor hysteresis loops of an initially demagnetized sample, plotted with progressively increasing maximum magnetic field, has been used. The obtained results showed excellent agreement with those calculated by the remanence curve method for a Stoner–Wohlfarth model system.

Determination of the Constants of Magnetocrystalline Anisotropy in Sintered Magnets with Uniaxial Texture

2005 ◽  
Vol 498-499 ◽  
pp. 134-140 ◽  
Author(s):  
Marcos Flavio de Campos
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Pole Figure ◽  
High Energy ◽  
Anisotropy Constant ◽  
Magnetization Curves ◽  
Easy Magnetization ◽  
Initial Magnetization ◽  
Usual Process

The usual process for producing the high energy magnets based on rare-earth-transition metals as for example NdFeB, SmCo5 or Sm(CoFeCuZr)z involves powder metallurgy. In many cases, it is necessary the determination of anisotropy constants (K1 – first order and K2 second order) from polycrystalline samples. This is not the ideal situation because for more accurate determinations a single crystal is necessary. Nevertheless, in many cases it is very difficult, or not possible, obtaining a single crystal. Then, for these situations, the anisotropy constants can be evaluated from polycrystalline samples with uniaxial texture. In this study, the methodology for making such determination is described. It includes the measurement of Schulz Pole figure by X-Ray diffraction in a surface perpendicular to the c-axis, the axis of easy magnetization. The measured Pole figure can be adjusted with a Gaussian distribution f(q)=exp(-q2/2s2) or with a distribution of type f(q) = cosn q. A model to evaluate the remanence from quantitative metallography is also described. From these distributions, and using the microstructural model, it is possible to estimate the initial magnetization curves for polycrystalline samples, including the effect of the 2nd order anisotropy constant (K2) which produces a curvature in initial magnetization curve. With all these data it is finally possible to estimate the initial magnetization curves for single crystal samples (theoretical), and the anisotropy constants K1 and K2. The inadequacy of Sucksmith-Thompson plots for determination of anisotropy constants from polycrystalline samples is also commented. The described method can be used either for rare-earth transition magnets or for Barium or Strontium ferrites.

scholarly journals Magnetization curves and hysteresis loops of nanostructured rare earth titanates

2018 ◽  
Vol 185 ◽  
pp. 03005
Author(s):  
Anatoly B. Rinkevich ◽  
Alexander V. Korolev ◽  
Mikhail I. Samoilovich ◽  
Sergej O. Demokritov ◽  
Dmitry V. Perov
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Hysteresis Loop ◽  
Magnetic Moment ◽  
Effective Magnetic Moment ◽  
Pyrochlore Structure ◽  
Hysteresis Loops ◽  
Nanocomposite Materials ◽  
Magnetization Curves ◽  
Crossing Point

Magnetic properties of the nanocomposite materials containing particles of rare earth titanates with pyrochlore structure have been investigated. For the nanocomposites with Gd2Ti2O7, La2Ti2O7 it has been observed that the effective magnetic moment in the nanocomposites differs substantially from that for Gd3+ and La3+ ions. The hysteresis loops was obtained for the nanocomposites with Dy3+, Gd3+, Yb3+, Er+, Sm3+ ions. There is no hysteresis loops for the nanocomposites with La2Ti2O7, Pr2Ti2O7 and Nd2Ti2O7 particles. It has been shown that nanocomposites with Yb2Ti2O7, Dy2Ti2O7 and Er2Ti2O7 particles have one crossing point on the descending branches of hysteresis loop in some temperature range.

Comparison of static hysteresis models subject to arbitrary magnetization waveforms

2017 ◽  
Vol 36 (3) ◽  
pp. 774-790 ◽  
Author(s):  
Martin Petrun ◽  
Simon Steentjes ◽  
Kay Hameyer ◽  
Drago Dolinar
Keyword(s):  
Design Methodology ◽  
Hysteresis Loops ◽  
Magnetization Curves ◽  
Hysteresis Model ◽  
Content Type ◽  
The Individual ◽  
Practical Implications ◽  
Excitation Waveform ◽  
Arbitrary Magnetization ◽  
Selection Of

Purpose This paper aims to compare different static history-independent hysteresis models (mathematical-, behavioural- and physical-based ones) and a history-dependent hysteresis model in terms of parameter identification effort and accuracy. Design/methodology/approach The discussed models were tested for distorted-excitation waveforms to explore their predictions of complex magnetization curves. Static hysteresis models were evaluated by comparing the calculated and measured major and minor static hysteresis loops. Findings The analysis shows that the resulting accuracy of the different hysteresis models is strongly dependent on the excitation waveform, i.e. smooth excitations, distorted flux waveforms, transients or steady-state regimes. Obtained results show significant differences between predictions of discussed static hysteresis models. Research limitations/implications The general aim was to identify the models on a very basic and limited set of measured data, i.e. if possible using only the measured major static loop of the material. The quasi-static major hysteresis loop was measured at Bmax = 1.5 T. Practical/implications The presented analysis allows selection of the most-suited hysteresis model for the sought-for application and appraisal of the individual limitations. Originality/value The presented analysis shows differences in intrinsic mechanisms to predict magnetization curves of the majority of the well-known static hysteresis models. The results are essential when selecting the most-suited hysteresis model for a specific application.

Demagnetizing correction in fluxmetric measurements of magnetization curves and hysteresis loops of ferromagnetic cylinders

2018 ◽  
Vol 449 ◽  
pp. 447-454 ◽  
Author(s):  
Du-Xing Chen ◽  
Enric Pardo ◽  
Yong-Hong Zhu ◽  
Li-Xiong Xiang ◽  
Jia-Quan Ding
Keyword(s):  
Hysteresis Loops ◽  
Magnetization Curves
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