[Wien] AFM type II

Wed Jan 29 13:23:13 CET 2020

Dear Gerhard,

nice ... thanks a lot for the references!

Best regards,

Martin

---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564

Am 2020-01-29 13:16, schrieb Fecher, Gerhard:
> Dear Martin,
> this concerns your remark:
> "With two magnetic species, say, Mn and Cu, you would wind up with
> different size of the moment on Mn and Cu. I know of no case where 
> exact
> compensation into an AFM structure occures by accident in such a
> situation."
> 
> You may have the situation of a completely compensated ferrimagnet 
> exampels are:
> CrMnSb (or VFeSb) in the cubic C1b structure
> H. van Leuken and R. A. de Groot, Phys. Rev. Lett. 74, 1171 (1995)
> or more complicated
> Mn1.5FeV0.5Al
> Rolf Stinshoff et al; Phys. Rev. B 95, 060410(R) (2017)
> 
> However, it is by purpose rather than by accident.
> 
> This was already found by Neel in his work on antiferromagnets
> (probably it is mentioned in the Nobel lecture)
> 
> 
> 
> 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 [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von
> pieper [pieper at ifp.tuwien.ac.at]
> Gesendet: Mittwoch, 29. Januar 2020 12:49
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] AFM type II
> 
> No one can give you an honest answer without knowing the structure you
> put these elements in. Zr, S, Se are almost certainely non-magnetic, 
> but
> there are quite a few structures with magnetic moments on Cr, Cu, and 
> of
> course on Mn.
> 
> To make terminology more complicated, remember that AFM means fully
> compensated magnetic moments. The net magnetization of a unit cell of
> some AFM structure is zero. This does not happen by coincidence, it is
> because by symmetry all moments have the same size, and there are as
> many of them pointing in one direction as there are pointing in exactly
> the opposite direction.
> 
> So, IF your compound REALLY is AFM by experiment (NO net 
> magnetization),
> you almost certainely have only one magnetic species in there (probably
> Mn). With two magnetic species, say, Mn and Cu, you would wind up with
> different size of the moment on Mn and Cu. I know of no case where 
> exact
> compensation into an AFM structure occures by accident in such a
> situation. You always get something with net moment - and these are
> called ferrimagnetic structures. And since we are at it: there are
> canted and helical strucutures where the moments are not collinear (not
> within the scope of Wien2k), there are spin density waves, ...
> 
> Scanning this thread my advice would be to study a (good) book on solid
> state physics, with special attention payed to its chapter discussing
> magnetic order. If it doesn't have such a chapter its not a good book -
> at least not for you. Do NOT use wikipedia or this mailing list and its
> archive as a substitute for such a reading. It will not work.
> 
> 
> ---
> Dr. Martin Pieper
> Karl-Franzens University
> Institute of Physics
> Universitätsplatz 5
> A-8010 Graz
> Austria
> Tel.: +43-(0)316-380-8564
> 
> 
> Am 2020-01-27 17:45, schrieb djamel slamnia:
>> WHEN I STUDY A COMPOUND CONTAINS THIS ELEMENETS CU  MN   CR  ZR S SE
>> 
>> BETWEEN THEM WITCH ONE TO PUT IT SPIN UP OR DOWN AND NON-MAGNETIC ???
>> 
>>  Le lundi 27 janvier 2020 à 14:22:39 UTC+1, Gavin Abo
>> <gsabo at crimson.ua.edu> a écrit :
>> 
>>  As previously mentioned [1], a short literature survey showed that
>> AFM type II and III are terms used for _fcc_ and _bcc_ lattices.
>> Since spacegroup 156 is not one of those, it might be inappropriate to
>> use those terms for spacegroup 156 having a _primitive_ lattice [2] of
>> the hexagonal crystal family.  If you do a more extensive literature
>> survey yourself and find a paper (article, book, etc.) that defines
>> the AFM magnetic orders for spacegroup 156, then reference and use it
>> for what the AFM order is.  If there is not any notations and terms
>> for AFM magnetic orders for spacegroup 156, you might have to make
>> your own figure or write in your own words what the definition is
>> should any AFM magnetic orders exist for it.
>> Keep in mind that as mentioned before in the mailing list archive, the
>> initial configuration can be set in case.inst with "instgen_lapw -ask"
>> [3].
>> 
>> Though, you need to check the final magnetic order that comes out of
>> the scf [4], because the configuration set in case.inst with
>> instgen_lapw is just the initial one that could change [5,6].
>> 
>> It is also possible to try to force a magnetic order using dmatup/dn
>> matrices but the final magnetic order is still what comes out of the
>> scf and could be different [6-11].
>> 
>> Therefore, it likely not beneficial to name the AFM order before
>> starting a calculation such that you would likely want to identify the
>> name of the magnetic order after having finished the converged
>> calculation.
>>  [1]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19515.html
>> [2] https://en.wikipedia.org/wiki/Crystal_structure#Lattice_systems
>> [3]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg10044.html
>> 
>> [4]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg17516.html
>> [5]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg03243.html
>> [6]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg06739.html
>> [7]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14259.html
>> [8]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg05054.html
>> [9]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg13124.html
>> [10]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16281.html
>> [11]
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16286.html
>> 
>> On 1/26/2020 1:01 PM, djamel slamnia wrote:
>> 
>>> 
>> 
>> THANKS AGAIN SIR
>> 
>> I NEED TO KNOW WHAT IS THE AFM ORDERS FOR P3M1 (156) ??? TYPE II OR
>> III
>> 
>> THANKS IN ADVANCE
>> 
>>> 
>> 
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