Curie temperature

[Om Prakash Upadhyay]

Hello.....
    I want to find the curie temperature for half metallic ferromagnetic nanowire by plotting a curve between magnetic moment versus temperature  obtained from ATK_DFT Mullikan population. (Actually, I have found that on increasing the temperature the magnetic moment decreases gradually, becomes almost zero for a certain region and attain negative value). Is it right method or not?
If not then how can I find the curie temperature.......
        Hope for easy and detailed answer.......
                                   Thanks in advance...............

[Petr Khomyakov]

You may find a detailed answer to your question,  for example, at https://www.researchgate.net/post/Curie_Temperature_Calculation_by_DFT_MD_calculations_vasp.

[Om Prakash Upadhyay]

thanks for reply...
     Its ok,  but I am working on ATK-DFT 2011.8.2. I am deciding to ploting a curve of temperature vs magnetic moment (magnetization) obtained from mulliken population which goes on decreasing , attain constant value about zero (critical temperature)(ferromagnetic material turned to paramagnetic) and then give negative value. Either this method is valid for DFT calculation or not?
Please give me detailed valid answer about it............

[Daniele Stradi]

Unfortunately, ATK 2011 is not supported anymore.

[Kim_W]

Can the 2022 version do this calculation? Plotting a curve curve magnetic moment versus temperature.

[filipr]

QuantumATK 2021.06 and newer can calculate the Heisenberg exchange couplings and from that one can estimate the Curie temperature through a mean-field approach, see: https://docs.quantumatk.com/tutorials/heisenberg_exchange/heisenberg_exchange.html

If you want to actually produce a plot of the magnetic moments vs temperature you need to use the calculated exchange couplings in a classical statistical Heisenberg model. This can be done since QuantumATK 2022.12, see: https://docs.quantumatk.com/tutorials/mram_vampire_workflow/mram_vampire_workflow.html

[Kim_W]

When I calculate the case according to the tutorial, the following error occurs, how to solve it? Thank u!
Initialising system variables
Creating system
Reading in unit cell data from disk...done!
Processing unit cell data...
Processing data for 27 atoms...done!
Processing data from 4280 interactions...done!
Verifying exchange interactions...Fatal error: Aborting program. See log file for details.

Vampire log output:
03-12-2023 [22:12:41] Logfile opened
03-12-2023 [22:12:41] Executable : C:\Program Files\QuantumATK\QuantumATK-V-2023.09\external_tools\vampire\vampire.exe
03-12-2023 [22:12:41] Host name  : DESKTOP-OTELUT8:
03-12-2023 [22:12:41] Directory  : E:\WQQ
03-12-2023 [22:12:41] Process ID : 15676
03-12-2023 [22:12:41] Version    : 6.0.0
03-12-2023 [22:12:41] Githash    : GHASH
03-12-2023 [22:12:41] Opening main input file "input".
03-12-2023 [22:12:41] Parsing system parameters from main input file.
03-12-2023 [22:12:41] Opening material file "input.mat".
03-12-2023 [22:12:41] Parsing material file for parameters.
03-12-2023 [22:12:41] Reading in unit cell data from disk...
03-12-2023 [22:12:41] Reading data completed. Processing unit cell data...
03-12-2023 [22:12:41]    Processing data for 27 unit cell atoms...
03-12-2023 [22:12:41]    Processing unit cell atoms completed
03-12-2023 [22:12:41]    Processing data from 4280 interactions...
03-12-2023 [22:12:41]    Processing unit cell interactions completed
03-12-2023 [22:12:41]    Verifying unit cell exchange interactions...
03-12-2023 [22:12:41] Error! Exchange interaction list in unit cell file input.ucf contains the following assymetric interactions: