Magnetic dipole-dipole interaction model

Hello,

I'd like to calculate magnetic dipole-dipole interaction energy.

Actually, I've tried to find models for the calculation, but most of them are just a simple point dipole-dipole interaction model.

I can't utilize this simple point dipole-dipole interaction model directly because I'm considering interaction between two ferromagnetic materials.

So I need to find effective or net magnetic dipole of each ferromagnetic materials as follows:



I believe this effective or net magnetic dipole may have finite length of dipole.

Is there any approximation or calculation method to get this?

I also wonder if I can assume this one as a single dipole (if I can get this) and apply to the point dipole-dipole interaction model.

Otherwise, should I use other models to get the magnetic dipole-dipole interaction between ferromagnetic materials?

Any assistance you can give me will surely be appreciated.


Warmest and best regards,

KHAN