STT or SOT

[Shipra Saini]

Hi all,
I’m still facing issues with STT and haven’t been able to figure out how to resolve it yet. Could someone please help?

Thanks and regards

[gabo...@gmail.com]

I don't know what issue or error message from the program you are encountering.

I'm providing an input file and a .mat file that I sloppy made that should be producing "Initialising data structures for spin torque calculation" after executing vampire-serial in the outputted log file should it help.

Disclaimer: The following likely needs further analysis and verification from someone else but making available as someone may want to adjust it to have more realistic parameters or for possibly making a better tutorial for the STT module.

I believe the output might be showing parallel to anti-parallel spin transfer torque switching of the free layer with perpendicular magnetism in a three layer stack:

username@computername:~/Desktop/stt$ ls -l
total 12
-rw-r--r-- 1 username username 1196 Mar 24 22:37 input
-rw-rw-r-- 1 username username  196 Mar 24 22:11 MvsTime.gnu
-rw-r--r-- 1 username username 2296 Mar 24 22:37 stack.mat
username@computername:~/Desktop/stt$ vampire-serial
                                                _          
                                               (_)        
                    __   ____ _ _ __ ___  _ __  _ _ __ ___
                    \ \ / / _` | '_ ` _ \| '_ \| | '__/ _ \
                     \ V / (_| | | | | | | |_) | | | |  __/
                      \_/ \__,_|_| |_| |_| .__/|_|_|  \___|
                                         | |              
                                         |_|              

                      Version 7.0.0 Feb  8 2026 19:17:30

             Git commit: 525bc27ee44c525aee229570f30f3d4c61d54f66

  Licensed under the GNU Public License(v2). See licence file for details.

  Developers:   Richard F L Evans, Sarah Jenkins, Andrea Meo,
                Daniel Meilak, Andrew Naden, Matthew Ellis,
                Oscar Arbelaez, Sam Morris, Rory Pond, Weijia Fan,
                Phanwadee Chureemart, Pawel Sobieszczyk, Joe Barker,
                Thomas Ostler, Andreas Biternas, Roy W Chantrell,
                Wu Hong-Ye, Razvan Ababei, Sam Westmoreland,
                Milton Persson
 
                Compiler Flags:

  Vampire includes a copy of the qhull library from C.B. Barber and The
  Geometry Center and may be obtained via http from www.qhull.org.

================================================================================
Tue Mar 24 23:21:47 2026
================================================================================
Initialising system variables
lsdl0 120
lsdl2 120
Creating system
Generating neighbour list..........done!
Copying system data to optimised data structures.
Using generic/normalised form of exchange interaction with 6 total interactions.
Number of atoms generated: 10933
Starting Simulation with Program Time-Series...
Simulation run time [s]: 0.222016
Simulation ended gracefully.
username@computername:~/Desktop/stt$ grep spin log
24-03-2026 [23:21:47] Initialising data structures for spin torque calculation.
username@computername:~/Desktop/stt$ gnuplot --persist MvsTime.gnu

Sincerely,

Gavin

VAMPIRE user