Strange thing in FCC Structure

[F Ξ L I P Ξ]

Hello Vampire Users! I'm facing something weird when I model an FCC structure. My code is to generate a cobalt fcc structure but is generating a single ucf grid, which can be seen in the image. Can anyone help me with this problem?

[gabo...@gmail.com]

Can you clarify what the problem is for you?

If you are trying to get a single fcc unit cell, the following might help.

There is a script file createfccfile.m that a user provided for creating a fcc ucf file at:

[1] https://groups.google.com/g/vampire-users/c/9ThHMDZk4h4/m/jUZZSpw2BwAJ

That script file I edited and put a lattice constant for fcc Co in to it, then I ran it with Octave to create the ucf file.

Some of the simulation parameters are likely not correct such as for the material parameters as I only adjusted some and not all of them to be for fcc Co but at least it looks like I got a fcc unit cell in rasmol by doing the following:

username@computername:~/Desktop/fcc$ lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 20.04.4 LTS
Release:    20.04
Codename:    focal
username@computername:~/Desktop/fcc$ ls -l
total 20
-rw-r--r-- 1 username username 12208 Apr  2 14:02 createfccfile.m
-rw-r--r-- 1 username username   711 Apr  2 14:05 fcc.mat
-rw-r--r-- 1 username username  1589 Apr  2 14:10 input
username@computername:~/Desktop/fcc$ octave createfccfile.m
...
username@computername:~/Desktop/fcc$ vampire-serial
                                                _          
                                               (_)        
                    __   ____ _ _ __ ___  _ __  _ _ __ ___
                    \ \ / / _` | '_ ` _ \| '_ \| | '__/ _ \
                     \ V / (_| | | | | | | |_) | | | |  __/
                      \_/ \__,_|_| |_| |_| .__/|_|_|  \___|
                                         | |              
                                         |_|              

                      Version 6.0.0 Dec 31 2021 01:00:23

             Git commit: 4c9651daecc86c3e6b6df0c8055fcd9e89fd900c

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

  Lead Developer: Richard F L Evans <richar...@york.ac.uk>

  Contributors: Sarah Jenkins, Andrea Meo, 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,
                Daniel Meilak
 
                Compiled with:  GNU C++ Compiler
                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.

================================================================================
Sat Apr  2 14:14:14 2022
================================================================================
Initialising system variables
Creating system
Reading in unit cell data from disk...done!
Processing unit cell data...
Processing data for 4 atoms...done!
Processing data from 48 interactions...done!
Verifying exchange interactions...done!
Generating neighbour list........done!
Copying system data to optimised data structures.
Using isotropic form of exchange interaction with 48 total interactions.
Number of atoms generated: 14
Starting Simulation with Program Curie-Temperature...
Simulation run time [s]: 1.05041
Monte Carlo statistics:
    Total moves: 2044000
    62.5137% Accepted
    37.4863% Rejected
Simulation ended gracefully.
username@computername:~/Desktop/fcc$ /home/username/vampire/util/vdc/vdc --xyz
|------------------------------------------------------------|
|              Vampire Data Converter for v5+                |
|------------------------------------------------------------|
Processing snapshot 00000000

In rasmol using Display -> Ball & Stick, the fcc unit cell appeared as seen in the attached "fcc_rasmol.png".

Kind Regards,

Gavin

VAMPIRE user

[gabo...@gmail.com]

You mentioned CoFe alloy in your previous post at:

https://groups.google.com/g/vampire-users/c/yFYgmj5y8X8/m/8NPGiy45BgAJ

If you doing something similar to L10 FeNi like that seen in Figure 1 of the article titled "Thermodynamics of f.c.c.-Ni–Fe Alloys in a Static Applied Magnetic Field" by I. V. Vernyhora et. al.:

https://doi.org/10.5402/2012/917836

My simulation parameters may not be correct, but should it help I did get a picture that looks like it as seen in the attached "fccFeNi.png".

username@computername:~/Desktop/fcc2element$ lsb_release -a

No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 20.04.4 LTS
Release:    20.04
Codename:    focal

username@computername:~/Desktop/fcc2element$ ls -l
total 12
-rw-r--r-- 1 username username  864 Apr  2 16:11 fcc2element.mat
-rw-rw-r-- 1 username username 2284 Apr  2 16:38 fcc2element.ucf
-rw-r--r-- 1 username username 1512 Apr  2 16:13 input
username@computername:~/Desktop/fcc2element$ vampire-serial

                                                _          
                                               (_)        
                    __   ____ _ _ __ ___  _ __  _ _ __ ___
                    \ \ / / _` | '_ ` _ \| '_ \| | '__/ _ \
                     \ V / (_| | | | | | | |_) | | | |  __/
                      \_/ \__,_|_| |_| |_| .__/|_|_|  \___|
                                         | |              
                                         |_|              

                      Version 6.0.0 Dec 31 2021 01:00:23

             Git commit: 4c9651daecc86c3e6b6df0c8055fcd9e89fd900c

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

  Lead Developer: Richard F L Evans <richar...@york.ac.uk>

  Contributors: Sarah Jenkins, Andrea Meo, 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,
                Daniel Meilak
 
                Compiled with:  GNU C++ Compiler
                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.

================================================================================

Sat Apr  2 16:39:40 2022

================================================================================
Initialising system variables
Creating system
Reading in unit cell data from disk...done!
Processing unit cell data...
Processing data for 4 atoms...done!
Processing data from 48 interactions...done!
Verifying exchange interactions...done!
Generating neighbour list........done!
Copying system data to optimised data structures.
Using isotropic form of exchange interaction with 48 total interactions.
Number of atoms generated: 14
Starting Simulation with Program Curie-Temperature...

Simulation run time [s]: 1.0894

Monte Carlo statistics:
    Total moves: 2044000
    62.5137% Accepted
    37.4863% Rejected
Simulation ended gracefully.

username@computername:~/Desktop/fcc2element$ /home/username/vampire/util/vdc/vdc --xyz

|------------------------------------------------------------|
|              Vampire Data Converter for v5+                |
|------------------------------------------------------------|
Processing snapshot 00000000

username@computername:~/Desktop/fcc2element$ rasmol -xyz crystal.xyz

Kind Regards,

Gavin

VAMPIRE user

On Friday, April 1, 2022 at 4:10:08 PM UTC-6 pcli...@gmail.com wrote:

[F Ξ L I P Ξ]

Good morning! My problem was in generating a continuous grid of fcc structures. I solved the problem! 

In the tuturial video on Youtube "Introduction to Anti-Ferromagnets" it is said that in UCF it is necessary to generate the structure with 2*a and with the coordinates of the acts divided in half, that is, if my UC goes from 0 to 1 then an atomo that is at the corner will have coordinated 0,0,0.5 instead of 0.0.1,   for example. I disregarded it and now I'm generating the structure the right way!

In the image i generate a fcc structure of Co0.75Ni0.25 alloy. 

But I'm still have another problems. I believe that my ucf file is correct, but when I simulate a Curie Temperature of pure Nickel, i get 100K, much under than the ~700K. I'm using exchange and spin moment from this article: https://www.researchgate.net/figure/Calculated-exchange-integrals-for-fcc-Co-and-fcc-Ni_tbl2_337594168