I’ve been trying to simulate permalloy disks in oommf and according to the theory, when a field is applied and then removed, the disk should settle into a perfect vortex to minimize it’s over energy just like in the beginning of the attached video. However, my simulation has the disks ending with different domain walls that don’t annihilate when the field is reduced to zero.

I tried using a bmp file and Imageatlas but that didn't seem to work either.

Simulation details

400 nm diameter disk

30 nm thickness

Mesh size: 10 nm X 10 nm X 30 nm

No Anisotropy

Evolver: Spinxfer

Driver: Time driver

If anyone has any suggestions, please let me know.

I'm using oommf 1.2 with prebuilt tcl (version 8.6.8) library on windows 10.