STT Implementation

[Vinod Naik Bhukya]

Hi everyone and Dr. Richard , 

This query is regarding the STT Slonczewski implementation . I have seen many posts in the forum, but nothing is clear. 

There are two folders in the vampire distribution: vampire/src/spintorque where in the interface.cpp file, the parameters for STT are mentioned. 

And the other folder is : vampire/src/simulate where in the interface.cpp, spin transfer and spin orbit torque parameters are mentioned. 

My first doubt is are these two different implementations or these have to be used combinedly. 

Second doubt is why there is absolutely zero information about these in the documentation. In other software documentations, there will be clear explanation of how a particular module is implemented. Because without knowing the actual equations used to implement that module a user will not understand different parameters. 

For example in the spin torque module, there are so many parameters, but what those parameters correspond to and in which equation they are used, no information is there in the documentation or in the code. 

My biggest surprise is whoever developed those modules and included in the vampire distribution, why they are not including these in the manual? what's the point of giving some features and not giving any documentation or examples to use that feature is ridiculous and strange. 

I kindly request the developers of spin torque module to please update the documentation or release a application note regarding its implementation and explanation of all the terms and the corresponding equations. Otherwise, it is very hard to validate the results. Please it is sincere request. I hope this will be addressed. 

Thank you. 

[gabo...@gmail.com]

At [1], you should see that it looks like A. Meo was a PhD student at the University of York.  You should see at [2] that an article that used the spin torque module was publish at [2].  Probably, the code was developed for VAMPIRE as part of their graduate studies.  My guess is completing degree requirements (courses, journal publications, dissertation) to graduate took away from them documenting it the manual.  I suppose since it was not documented in the manual, the VAMPIRE developers could have not included the spin torque module in the source code.  However, I think we are fortunate to have the source code even though it is undocumented.  From the Linkedin page at [3], it looks like Dr. Meo left the University of York and could now be an assistant professor at Politecnico di Bari in Italy.

You might not have been a member of the VAMPIRE group at the time, but there was an announcement at [4] by the VAMPIRE developers looking for someone that could help with manual entries. Your observation about the state of the manual seems to suggest they are likely still looking for volunteers to help with that.  This should hopefully answer your question about why there is no information about the spin torque module in the VAMPIRE manual.

Also, it might be of interest to you that I saw a VAMPIRE workshop coming up in February 2026.  It might be an opportunity for a person to ask the VAMPIRE developers questions and get some answers.  More details on that you should find at [5].

In addition, since A. Meo's dissertation titled "Atomistic model of magnetisation dynamics and equilibrium properties of magnetic tunnel junctions" might include equations on the spin torque you are looking for.  I include a link [6] that should go to it.

[1] https://www-users.york.ac.uk/~am1808/
[2] https://dx.doi.org/10.1088/1361-648X/ac9c80
[3] https://it.linkedin.com/in/andrea-meo-4b360094?trk=public_profile_browsemap
[4] https://groups.google.com/g/vampire-users/c/Dcb9wCMqQQc/m/GGlThr9JBwAJ

[5] https://groups.google.com/g/vampire-users/c/dmEYOfEhkYA/m/yia_Ad4mAgAJ

[6] https://etheses.whiterose.ac.uk/id/eprint/22730/

Sincerely,
Gavin

VAMPIRE user

[Richard Evans]

Hi both,

I have added some basic documentation on using STT in the new version of the manual, as well as general updates to the software. Their omission from the manual was an oversight on my part.

Cheers,

Richard

[Vinod Naik Bhukya]

Thank you so much. 

richard....@gmail.com 在 2025年6月6日 星期五晚上7:34:03 [UTC+8] 的信中寫道：

[Vinod Naik Bhukya]

I have one doubt which is still unclear. Is spin-torque a different module ?

richard....@gmail.com 在 2025年6月6日 星期五晚上7:34:03 [UTC+8] 的信中寫道：

Hi both,