[femm] Problems with non-linear B-H-curves

[Kuepferling Michaela <kuepfer@xxxxxxxxxxxxxxxxxx>]

In our group at the Vienna University of Technology we measure magnetic
materials with magnetic pulse fields. I wanted to compare a
hysteresis-measurement of a Ni-sphere with a radius of 4.85mm with the
results of FEMM. The following questions arised: I got with FEMM B~8.3T
inside the sphere (see the attached file NiBr2.EMF). But with the applied
field of ~5.2T and J(Ni)~0.6T, when Ni is saturated, B becomes about 5.8T.
Why is the calculated B so high? The other problem is, that we expected a
decay of B inside the sphere because of the induced eddy currents. But with
FEMM I found an increase of B with decreasing radius (see the attached file
NiBrki.EMF).
I welcome any comments! 
Michaela Küpferling

Attachment: NiBrki.EMF
Description: Binary data

Attachment: NiBr2.EMF
Description: Binary data