Specifying a demagnetization curve of a permanent magnet

Hi all,

I use the magnetic fields interface (AC/DC module) to simulate a magnetic system with permanent magnets and soft iron parts.

Currently I use the "remanent flux density" constitutive relation (B = mu0 * mur * H + Br) for the permanent magnet domain of the model, with Br=constant and mur=1.

However, I have realized that this is likely not a sufficiently accurate model of the permanent magnet. I have attached a demagnetization plot (J vs. H) of our magnet with the load line marked, and I think that I need to include the complete curve and not just the specifying a value for the remanent flux density as the intrinsic flux density is highly dependent on the field strength.

The magnetic fields interface solve my model for the magnetic vector potential, A, as the dependent variable. In this case, I believe, that I need to express the material properties as functions of the magnetic flux density B, to avoid a circular variable definition (e.g. the permeability, mur, of the soft iron parts is specified as a functions of the magnetic flux density, B).

My question is: How can I specify the demagnetization curve of the permanent magnet in my model?

Thanks in advance,
Johan Gustafsson