addition of stress field

[KL K]

Hello everyone. I would like to ask if there is a way to add a stress field in mumax3? If possible, how should I do it? Is it introduced through the magnetostrictive coefficient? Thank you all.

[Josh Lauzier]

Hi,

In base mumax3, you can include an effective field. You need to set the magneto-elastic coupling constants B1 and B2, as well as some nonzero strain. The various components of the strain tensor are exx,exy, etc. 

A couple notes when setting these: B2 usually isn't zero, so make sure to set both B1 and B2. If you only have the magnetostrictive coefficient lambda, you can relate them to B1 and B2 using (for cubic symmetry)  lambda_100=-2/3*((B1)/(c11-c12)) and lambda_111=-(B2)/(3*c44) (see here for more detail) . Also note the signs- they are important.

(Depending on what you're interested in, you may also want to look at the magnetoelastic module or mumaxplus+. Instead of just using an effective magnetic field term, they full simulate the elastic dynamics as well as the magneto-elastic coupling. But if you only care about the magnetic response, the effective field approach in mumax3 is fine)

Best,
Josh L.