Grain boundraies / ext_ScaleExchange()

[Muhammad Hassaan]

Hello everyone,

I am working on a polycrystalline micromagnetic model in MuMax3. My model contains different grains, and normally I can introduce grain boundaries to reduce the magnetic interaction between neighboring grains.

However, before explicitly creating grain-boundary regions, I wanted to test whether I can weaken the exchange interaction directly between grains using the command:

ext_ScaleExchange(int, int, float)

I have tried using this command to reduce the exchange coupling between different grain regions, but the results are not what I expected. The hysteresis behavior does not change in the way I expected when the interaction between grains is weakened.

Has anyone here used ext_ScaleExchange() for reducing exchange interaction between grains in a polycrystalline model?

I would like to know:

1) Is ext_ScaleExchange() suitable for modeling weak inter-grain exchange coupling?

2) Is there any recommended way to verify that the command is actually working?
3) Would it be better to create explicit grain-boundary regions instead of only scaling the exchange between grains?

Any suggestions or example scripts would be very helpful.

Thank you very much.

Bests,
Muhammad Hassaan