[Wien] Position of Atoms in AFM calculation.

[Fecher, Gerhard]

Dear Pablo you are wrong
Below you find that Murugan uses for the AFM set up

Dy 1 (000) and Dy2 (0.5,0.5,0.5 )
Pd(0.25,0.25,0.25) Bi (0.75,0.75,0.75) .

put it in space group 216 and use XCrysden to see the result, it is NOT DyPdSb
try what happens if you don't name Dy 1 and 2 but leave it open in the structure generator
I think the symmetry will be changed to F m-3m (225) instead of  F -43m (216).

For an so called half-Heusler structure you will find different types of AFM order that are described in different space groups (or say better that result in diferent symmetries)
fort example if Nd is the atom where the magnetic moments couple antiferromagnetically than you may have
AFM-I   ==> P -4m2 (113)
AFM-II  ==>  R 3m (160)
AFM-III ==> I -42d (122)

Now, before asking what is the correct structure, one needs to think about what one likes to do.





Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden
________________________________________
Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von delamora [delamora at unam.mx]
Gesendet: Donnerstag, 30. April 2015 17:31
An: A Mailing list for WIEN2k users
Cc: gtavizon
Betreff: Re: [Wien] Position of Atoms in AFM calculation.

Gerhard,
No, Murugan is right, it is DyPdBi
Although I found in the structure base "find it"
a=b=c=6.643
Dy: 0,0,0
Pd: 3/4,3/4,3/4
Bi: 1/2,1/2,1/2 and Murugan has 1/4,1/4,1/4
In terms of frustration this difference does not make a difference, since Bi is magnetically "neutral".
        Saludos

                    Pablo
________________________________________
De: wien-bounces at zeus.theochem.tuwien.ac.at <wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de Fecher, Gerhard <fecher at uni-mainz.de>
Enviado: jueves, 30 de abril de 2015 10:05 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Position of Atoms in AFM calculation.

No. its wrong
now you have Dy2PdBi instead of DyPdBi

you need to make a suitable supercell, or use a P instead of a F cell and distinguish the Dy atoms in a suitable way such that you can set spins of opposite direction
you also will need LDA+U, otherwise the Nd 4f states will appear at the Fermi energy

A description of different types of AFM order in Heusler compounds are given in the Landolt Börnstein (I don't remember the issue)

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden
________________________________________
Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Murugan Sundareswari [sundare65wien at gmail.com]
Gesendet: Donnerstag, 30. April 2015 15:42
An: A Mailing list for WIEN2k users
Betreff: [Wien] Position of Atoms in AFM calculation.

Dear wien 2k users
 I am working on the compound DyPdBi. this compound is anti ferromagnetic upto 3.5K(experimental report). crystal structure is MgAgAs  (216) .Dy (0,0,0),
Pd (0.75,0.75,0.75) and Bi(0.25,0.25,0.25)
I performed PBEsol calculation  for above mentioned positions without considering AFM.  I plotted band and DOS.
 Now i want to do AFM calculation again. I followed the steps given ,before trying with new compound i did for Cr, NiO.
 In my structure file   for AFM calculation the position of each compound is as follows
Dy 1 (000) and Dy2 (0.5,0.5,0.5 )
Pd(0.25,0.25,0.25) Bi (0.75,0.75,0.75) . Am i correct . i am not sure of the positions.
some one please confirm or correct me.
Thanks in advance.












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