How can I acquire the hysteresis loop when stress is applied to the sample?

[kurasaki]

hello everyone 

 What should I add to the script below to obtain the hysteresis loop of the stressed state?

 that's all, thank you very much.

[Josh Lauzier]

Hello,

You can set components of the strain tensor using 

exx=1e-3

(Similarly for exy, eyz, etc). You'll also need to set the magnetoelastic coupling terms B1 and B2. You can otherwise compute the hysteresis loop as normal.

Best,

Josh L.

[kurasaki]

Thanks for the reply.

I see that I just need to set the 8 items below.

exx,eyy,ezz,exy,eyz,ezx
B1 ,B2

And how are these 8 items determined? I would appreciate it if you could tell me.

Best regards

2022年12月14日水曜日 6:01:16 UTC+9 Josh Lauzier:

[Josh Lauzier]

Hi,

B1 and B2 are material parameters, the values of which you can usually find in the literature for most materials. Often, experimentally the magnetostrictive constant λ is reported instead. For cubic crystals, the relationship is  λ_100=-2/3*((B_1)/(c_11-c_12)) and  λ_111=-1/3*((B_2)/(c_44)).  where λ_100 or λ_111 is the magnetostriction along the 100 axis and 111 axis, and c_11,c_12,and c_14 are the elastic material parameters from the strain tensor (also easy to find in the literature).

For isotropic films, B_1=B_2. (For polycrystalline, one needs to take care. Sometimes it is assumed λ_100=λ_111=λ for polycrystalline , but this isn't quite right. It is generally a weighted average, since it's not truly isotropic. The book by Etienne du Trémolet de Lacheisserie has a good discussion of this).

For exx,eyy, etc, that corresponds to the amount of strain you want to study. So if your film is 0.1% strained in the +x-direction, that corresponds to exx=1e-3. So that will be determined by what you want to study

Best,

Josh L.