clarification on choosing the field-like torque parameter (ξ SOT ) in MuMax3

[Sandhya Ravi]

Dear MuMax3 community,

I am simulating SOT-driven domain wall motion in a Pt/Co nanostrip using MuMax3. In my implementation, the field-like torque is defined as

bj=ξSOT​×aj,

where aj is the damping-like torque strength.

I have seen ξSOT​=−2 used in several MuMax3 simulation codes and also in some research papers. I would like to understand how this value is chosen.

Is ξSOT​=−2 a commonly adopted simulation parameter, or should ξSOT​ always be chosen from experimentally measured FLT/DLT ratios for the specific material system (Pt/Co)? 

Thank you for your guidance.