Jiles-Atherton model

The Jiles-Atherton model of magnetic hysteresis was introduced in 1984.^[1] This is one of the most popular models of magnetic hysteresis. Its main advantage is the fact that this model enables connection with physical parameters of the magnetic material.^[2] Jiles-Atherton model enables calculation of minor and major hysteresis loops.^[1] The original Jiles-Atherton model is suitable only for isotropic materials.^[1] However, an extension of this model presented by Ramesh et al.^[3] and corrected by Szewczyk ^[4] enables the modeling of anisotropic magnetic materials.

Principles

Magnetization $M$ of the magnetic material sample in Jiles-Atherton model is calculated in the following steps ^[1] for each value of the magnetizing field $H$:

• effective magnetic field $H_\text{e}$ is calculated considering interdomain coupling $\alpha$ and magnetization $M$,
• anhysteretic magnetization $M_\text{an}$ is calculated for effective magnetic field $H_\text{e}$,
• magnetization $M$ of the sample is calculated by solving ordinary differential equation taking into account sign of derivative of magnetizing field $H$ (which is the source of hysteresis).

Parameters

Original Jiles-Atherton model considers following parameters:^[1]

Parameter	Units	Description
$\alpha$		Quantifies interdomain coupling in the magnetic material
$a$	A/m	Quantifies domain walls density in the magnetic material
$M_\text{s}$	A/m	Saturation magnetization of material
$k$	A/m	Quantifies average energy required to break pinning site in the magnetic material
$c$		Magnetization reversibility

Extension considering uniaxial anisotropy introduced by Ramesh et al.^[3] and corrected by Szewczyk ^[4] requires additional parameters:

Parameter	Units	Description
$K_\text{an}$	$J/m^3$	Average anisotropy energy density
$\psi$	rad	Angle between direction of magnetizing field $H$ and direction of anisotropy easy axis
$t$		Participation of anisotropic phase in the magnetic material

Modelling the magnetic hysteresis loops

Effective magnetic field

Effective magnetic field $H_\text{e}$ influencing on magnetic moments within the material may be calculated from following equation:^[1]

$H_\text{e}=H+\alpha M$

This effective magnetic field is analogous to the Weiss mean field acting on magnetic moments within a magnetic domain.^[1]

Anhysteretic magnetization

Anhysteretic magnetization can be observed experimentally, when magnetic material is demagnetized under the influence of constant magnetic field. However, measurements of anhysteretic magnetization are very sophisticated due to the fact, that the fluxmeter has to keep accuracy of integration during the demagnetization process. As a result, experimental verification of the model of anhysteretic magnetization is possible only for materials with negligible hysteresis loop.^[4]
Anhysteretic magnetization of typical magnetic material can be calculated as a weighted sum of isotropic and anisotropic anhysteretic magnetization:^[5]

$M_\text{an}= (1-t) M_\text{an}^\text{iso}+ t M_\text{an}^\text{aniso}$

Isotropic

Isotropic anhysteretic magnetization $M_\text{an}^\text{iso}$ is determined on the base of Boltzmann distribution. In the case of isotropic magnetic materials, Boltzmann distribution can be reduced to Langevin function connecting isotropic anhysteretic magnetization with effective maqnetic field $H_\text{e}$:^[1]

$M_\text{an}^\text{iso}=M_\text{s}(\coth(H_\text{e}/a)-(a/H_\text{e}))$

Anisotropic

Anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ is also determined on the base of Boltzmann distribution.^[3] However, in such a case, there is no antiderivative for Boltzmann distribution function.^[4] For this reason, integration has to be made numerically. In the original publication, anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ is given as:^[3]

$M_\text{an}^\text{aniso}=M_\text{s}\frac{\int_0^\pi \! e^{E(1)+E(2)}\sin(\theta)\cos(\theta)\,d\theta}{\int_0^\pi \! e^{E(1)+E(2)}\sin(\theta)\,d\theta}$

where

$E(1)=\frac{H_\text{e}}{a}\cos\theta-\frac{K_\text{an}}{M_\text{s} \mu_0 a} \sin^2(\psi-\theta)$

$E(2)=\frac{H_\text{e}}{a}\cos\theta-\frac{K_\text{an}}{M_\text{s} \mu_0 a} \sin^2(\psi+\theta)$

It should be highlighted, that typing mistake happened in the original Ramesh et al. publication.^[4] As a result, for isotropic material (where $K_\text{an}=0)$), presented form of anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ is not coherent with isotropic anhysteretic magnetization $M_\text{an}^\text{iso}$ given by Langevin equation. Physical analysis leads to conclusion, that equation for anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ has to be corrected to the following form:^[4]

$M_\text{an}^\text{aniso}=M_\text{s}\frac{\int_0^\pi \! e^{0.5(E(1)+E(2))}\sin(\theta)\cos(\theta)\,d\theta}{\int_0^\pi \! e^{0.5(E(1)+E(2))}\sin(\theta)\,d\theta}$

In the corrected form, model for anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ was confirmed experimentally for anisotropic amorphous alloys.^[4]

Magnetization as a function of magnetizing field

In Jiles-Atherton model, M(H) dependence is given in form of following ordinary differential equation:^[6]

$\frac{dM}{dH}=\frac{1}{1+c}\frac{M_\text{an}-M}{\delta k-\alpha(M_\text{an}-M)}+\frac{c}{1+c}\frac{dM_\text{an}}{dH}$

where $\delta$ depends on direction of changes of magnetizing field $H$ ($\delta = 1$ for increasing field, $\delta = -1$ for decreasing field)

Flux density as a function of magnetizing field

Flux density $B$ in the material is given as:^[1]

$B(H)=\mu_0M(H)$
where $\mu_0$ is magnetic constant.

Numerical problems

Two most important computational problems connected with the Jiles-Atherton model were identified:^[7]

• numerical integration of the anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$
• solving the ordinary differential equation for $M(H)$ dependence.

For numerical integration of the anisotropic anhysteretic magnetization $M_\text{an}^\text{aniso}$ the Gauss–Kronrod quadrature formula has to be used. In GNU Octave this quadrature is implemented as quadgk() function. For solving ordinary differential equation for $M(H)$ dependence, the Runge–Kutta methods are recommended. It was observed, that the best performing was 4-th order fixed step method.^[7]

Further development

Since its introduction in 1984, Jiles-Atherton model was intensively developed. As a result, this model may be applied for the modeling of:

• frequency dependence of magnetic hysteresis loop in conductive materials ^[8][9]
• influence of stresses on magnetic hysteresis loops ^[10][11][12]
• magnetostriction of soft magnetic materials ^[10][13]

Moreover, different corrections were implemented, especially:

• to avoid unphysical states when reversible permeability is negative ^[14]
• to consider changes of average energy required to break pinning site ^[15]

Applications

Jiles-Atherton model may be applied for modeling:

• rotating electric machines ^[16]
• power transformers ^[17]
• magnetostrictive actuators ^[18]
• magnetoelastic sensors ^[19][20]
• magnetic field sensors (e. g. fluxgates) ^[21][22]

It is also widely used for electronic circuit simulation, especially for models of inductive components, such as transformers or chokes.^[23]

References

1. Jiles, D. C.; Atherton, D.L. (1984). "Theory of ferromagnetic hysteresis". Journal of Applied Physics 55: 2115. Bibcode:1984JAP....55.2115J. doi:10.1063/1.333582.
2. Liorzou, F.; Phelps, B.; Atherton, D. L. (2000). "Macroscopic models of magnetization". IEEE Transactions on Magnetics 36 (2): 418. Bibcode:2000ITM....36..418L. doi:10.1109/20.825802.
3. Ramesh, A.; Jiles, D. C.; Roderick, J. M. (1996). "A model of anisotropic anhysteretic magnetization". IEEE Transactions on Magnetics 32 (5): 4234. Bibcode:1996ITM....32.4234R. doi:10.1109/20.539344.
4. Szewczyk, R. (2014). "Validation of the anhysteretic magnetization model for soft magnetic materials with perpendicular anisotropy". Materials (MDPI) 7 (7): 5109. Bibcode:2014Mate....7.5109S. doi:10.3390/ma7075109. Retrieved 13 July 2014.
5. Jiles, D.C.; Ramesh, A.; Shi, Y.; Fang, X. (1997). "Application of the anisotropic extension of the theory of hysteresis to the magnetization curves of crystalline and textured magnetic materials". IEEE Transactions on Magnetics 33 (5): 3961. Bibcode:1997ITM....33.3961J. doi:10.1109/20.619629.
6. Jiles, D. C.; Atherton, D.L. (1986). "A model of ferromagnetic hysteresis". Journal of Magnetism and Magnetic Materials 61: 48. Bibcode:1986JMMM...61...48J. doi:10.1016/0304-8853(86)90066-1.
7. Szewczyk, R. (2014). "Computational problems connected with Jiles-Atherton model of magnetic hysteresis". Advances in Intelligent Systems and Computing (Springer) 267: 275. doi:10.1007/978-3-319-05353-0_27.
8. Jiles, D.C. (1994). "Modelling the effects of eddy current losses on frequency dependent hysteresis in electrically conducting media". IEEE Transactions on Magnetics 30 (6): 4326. Bibcode:1994ITM....30.4326J. doi:10.1109/20.334076.
9. Szewczyk, R.; Frydrych, P. (2010). "Extension of the Jiles-Atherton model for modelling the frequency dependence of magnetic characteristics of amorphous alloy cores for inductive components of electronic devices" (PDF). Acta Physica Polonica A 118 (5): 782.
10. Sablik, M.J.; Jiles, D.C. (1993). "Coupled magnetoelastic theory of magnetic and magnetostrictive hysteresis". IEEE Transactions on Magnetics 29 (4): 2113. Bibcode:1993ITM....29.2113S. doi:10.1109/20.221036.
11. Szewczyk, R.; Bienkowski, A. (2003). "Magnetoelastic Villari effect in high-permeability Mn-Zn ferrites and modeling of this effect". Journal of Magnetism and Magnetic Materials 254: 284. Bibcode:2003JMMM..254..284S. doi:10.1016/S0304-8853(02)00784-9.
12. Jackiewicz, D.; Szewczyk, R.; Salach, J.; Bieńkowski, A. (2014). "Application of extended Jiles-Atherton model for modelling the influence of stresses on magnetic characteristics of the construction steel" (PDF). Acta Physica Polonica A 126 (1): 392.
13. Szewczyk, R. (2006). "Modelling of the magnetic and magnetostrictive properties of high permeability Mn-Zn ferrites". PRAMANA-Journal of Physics 67 (6): 1165. Bibcode:2006Prama..67.1165S. doi:10.1007/s12043-006-0031-z.
14. Deane, J.H.B. (1994). "Modeling the dynamics of nonlinear inductor circuits". IEEE Transactions on Magnetics 30 (5): 2795. Bibcode:1994ITM....30.2795D. doi:10.1109/20.312521.
15. Szewczyk, R. (2007). "Extension of the model of the magnetic characteristics of anisotropic metallic glasses". Journal of Physics D: Applied Physics (IOP) 40: 4109. Bibcode:2007JPhD...40.4109S. doi:10.1088/0022-3727/40/14/002.
16. Du, Ruoyang; Robertson, Paul (2015). "Dynamic Jiles–Atherton Model for Determining the Magnetic Power Loss at High Frequency in Permanent Magnet Machines". IEEE Transactions on Magnetics 51 (6): 7301210. doi:10.1109/TMAG.2014.2382594.
17. Huang, Sy-Ruen; Chen, Hong-Tai; Wu, Chueh-Cheng; et al. (2012). "Distinguishing internal winding faults from inrush currents in power transformers using Jiles-Atherton model parameters based on correlation voefficient". IEEE Transactions on Magnetics 27 (2): 548. doi:10.1109/TPWRD.2011.2181543.
18. Calkins, F.T.; Smith, R.C.; Flatau, A.B. (2008). "Energy-based hysteresis model for magnetostrictive transducers". IEEE Transactions on Magnetics 36 (2): 429. Bibcode:2000ITM....36..429C. doi:10.1109/20.825804.
19. Szewczyk, R.; Bienkowski, A. (2004). "Application of the energy-based model for the magnetoelastic properties of amorphous alloys for sensor applications". Journal of Magnetism and Magnetic Materials 272: 728. Bibcode:2004JMMM..272..728S. doi:10.1016/j.jmmm.2003.11.270.
20. Szewczyk, R.; Salach, J.; Bienkowski, A.; et al. (2012). "Application of extended Jiles-Atherton model for modeling the magnetic characteristics of Fe41.5Co41.5Nb3Cu1B13 alloy in as-quenched and nanocrystalline State". IEEE Transactions on Magnetics 48 (4): 1389. Bibcode:2012ITM....48.1389S. doi:10.1109/TMAG.2011.2173562.
21. Szewczyk, R. (2008). "Extended Jiles-Atherton model for modelling the magnetic characteristics of isotropic materials" (PDF). Acta Physica Polonica A 113 (1): 67.
22. Moldovanu, B.O.; Moldovanu, C.; Moldovanu, A. (1996). "Computer simulation of the transient behaviour of a fluxgate magnetometric circuit". Journal of Magnetism and Magnetic Materials (Elsevier). 157-158: 565. Bibcode:1996JMMM..157..565M. doi:10.1016/0304-8853(95)01101-3.
23. Cundeva, S. (2008). "Computer simulation of the transient behaviour of a fluxgate magnetometric circuit" (PDF). Serbian Journal of Electrical Engineering 5 (1): 21. doi:10.2298/sjee0801021c.

External links

• Jiles-Atherton model for Octave/MATLAB - open-source software for implementation of Jiles-Atherton model in GNU Octave and Matlab