Néel temperature

Posted on : April 04, 2017 (Tue) 07:50:55

by Karima

Dear KKR users,

Do you have any idea about how to calculate Néel temperature using KKR code.

[Re:04] Néel temperature

Posted on : April 04, 2017 (Tue) 08:51:58

by Karima

Thank you very much for your detailed explanation

[Re:03] Néel temperature

Posted on : April 04, 2017 (Tue) 08:47:53

by Administrator

Dear Karima,

the total energy calculated by the code is the energy per unit-cell. However, in the mean field theory, the magnetic energy to be consider is the energy per magnetic ion. Therefore, if the unit cell contains more than one magnetic ion, this has to be taken into account. For example antiferromagnetic KMnF3 contains two Mn atoms that couples antiferromagnetically to each other. The total energy has to be divided by 2 in this case. Similar happen for ferromagnetic systems with a complex structure: e.g., Nd2Fe14B contains 56 Fe atoms, then the total energy difference should be divided by 56.

[Re:02] Néel temperature

Posted on : April 04, 2017 (Tue) 08:33:07

by Karima

thank you very much for your answer and I would be very grateful if you could give me more explanation on the influence of the number of ions on the curie temperature as well as that of neel.

[Re:01] Néel temperature

Posted on : April 04, 2017 (Tue) 08:15:07

by Administrator

Dear Karima,

you can calculate Neel temperature by just the same procedure as that for Curie temperature: calculate the antiferromagnetic ground state and compare the energy with the LMD sites. Be carful about the fact that the antiferromagnetic structure normally contains more than one magnetic ions. You have to divide the energy difference by the number of magnetic ions in order to get a proper Neel temperature (the same may happen even in some ferromagnetic cases).

Best regards,

KKR Administrators