Differences between simulated and experimental hysteresis loops

[Zhiyu Zhang]

Hi Serban,

I would like to use Boris to simulate a hysteresis loop for a real sample, such as CoPt, which exhibits out-of-plane magnetization. In experiments, when measuring magnetism using VSM, its out-of-plane coercive field is very small, around 1 mT. However, when sweeping the in-plane field, the magnetic saturation field can be as high as 300 mT. But when I use Boris for the simulation, I cannot obtain such a result. Instead, the saturation fields for both in-plane and out-of-plane are almost the same.

Best regards,  
Zhiyu

[Serban Lepadatu]

Hi Zhiyu,

You need to set a uniaxial anisotropy (enable aniuni module) with easy axis perpendicular to the plane (set ea1 parameter to 0 0 1); you also need to set the K1 parameter (2nd order term anisotropy energy density). In this case you should get a square hysteresis loop perpendicular to the plane, and a hard-axis loop in the plane.

Kind regards,

Serban

[Zhiyu Zhang]

  Thank you for your response. Based on this, how should I set the parameters in Boris to ensure that the out-of-plane saturation field is much smaller than the in-plane saturation field?  

[Serban Lepadatu]

You do it by introducing anisotropy - please see my previous message.