Simulations of current-drived skyrmions

[Kaiying Dou]

Dear users,

I want to simulate the current-drived skyrmions in VAMPIRE. I found 'current-density' and 'current-direction' can be set in input file and I try to set it in simulations, but it cannot work. Skyrmions do not move in results. (The input file, *.ucf file and *.mat file are attached.  )

My questions are:

[1] How to simulate the movement of skyrmions in VAMPIRE, can you give me an example

[2] How to use the 'current-direction' and 'current-density' in input file

Thanks and Regards

Dou Kaiying

[Gavin Abo]

I read at [1] that Dou was able to set current-density in the input file using the line:

spin-torque:current-density=0.1e12

However, it is also mentioned by that VAMPIRE user that it had no effect on the outputted results.

I suspect that the spin-torque module would need to be enabled for the current-density to work.

In interface.cpp [2], lines 146-160 have:

      // Check for valid key, if no match return false
      std::string prefix="spin-torque";


      if(key!=prefix) return false;

      //----------------------------------
      // Now test for all valid options
      //----------------------------------

      std::string test="enable-ST-fields";

       if(word==test){
         st::internal::enabled = true;
         return true;
       }

The initialise.cpp [3] has on lines 51-54:

    if(st::internal::enabled==false) return;

   // output informative message
   zlog << zTs() << "Initialising data structures for spin torque calculation." << std::endl;

From the above lines of code, it looks like the spin-torque module can be enabled by putting in the input file the line:

spin-torque:enable-ST-fields

[1] https://groups.google.com/g/vampire-users/c/xP0hVuJa104/m/EFSH4LBgBgAJ

[2] https://github.com/richard-evans/vampire/blob/v6.0/src/spintorque/interface.cpp

[3] https://github.com/richard-evans/vampire/blob/v6.0/src/spintorque/initialise.cpp

Kind Regards,

Gavin

VAMPIRE user

--
You received this message because you are subscribed to the Google Groups "Vampire Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to vampire-user...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/vampire-users/80c32788-ddcf-4b72-bd8e-3de24154fba5n%40googlegroups.com.

[栗宇航]

Hi Kaiying and Gavin,

Is this problem solved? I tried "spin-torque:enable-ST-fields" but it still does work. 

Best wishes,

Yuhang

[gabo...@gmail.com]

I don't know if it was solved, and I never fiddled around with the spin-torque module more.

I recently came across a dissertation titled "Magnetisation Dynamic in Magnetic Tunnel Junctions (MTJs) Structure" by S. Sampan-apai [1] that has an input file with spin-torque:enable-ST-fields.  However, I have not tried that input file.

[1] http://202.28.34.124/dspace/handle/123456789/1897

Kind Regards,

Gavin

VAMPIRE user

[Vinod Naik Bhukya]

Any update on this????

gabo...@gmail.com 在 2024年10月23日 星期三中午12:26:31 [UTC+8] 的信中寫道：

[Gavin Abo]

I put that to the side and never got back to to running the VAMPIRE program for learning how to use the spin torque module.  I believe the other users that were trying to use the module never reported back if they were able to use it or how they used it.

Kind Regards,

Gavin

VAMPIRE user

To view this discussion visit https://groups.google.com/d/msgid/vampire-users/fafca2b0-b5e1-4c69-a853-f26bdc1f6907n%40googlegroups.com.