[Wien] paramagnetic or diamagnetic

[karima Physique]

Thank you very much for your answers

2017-05-08 20:19 GMT+02:00 Peter Blaha <pblaha at theochem.tuwien.ac.at>:

> In an insulator/semiconductor you have only the orbital part of the
> susceptibility. This can be calculated using our NMR package and such a
> material will be diamagnetic.
>
> In metals you have in addition a spin suszeptibility, which you can
> trivially calculate using spin-polarized calc. and an external field.
> Usually this part is paramagnetic. And then you have to see, which part
> dominates ....
>
> See also our NMR package.
>
>
> Am 08.05.2017 um 16:28 schrieb Fecher, Gerhard:
>
>> I am afraid that this question can not be answered
>> and I doubt if any answer on this can be generalised to all kinds of
>> materials.
>>
>> As an experimentalist my answer will be: measure the susceptibility and
>> it will tell you what your material is.
>>
>> As you do not apply any magnetic field in your (non-spinpolarized)
>> calculation, the induced magnetic moment will be zero
>> and a) tells you that this is true for both, diamagnetic or paramagnetic
>>
>> What about b) ?
>> I tried it for Pt and indeed I find that the application of a magnetic
>> field induces a magnetic moment (spin polarized calculation !)
>> that is parallel to the applied field, and linearly dependent on its
>> size, as expected for a paramagnet.
>> However, I did not check whether the electrons in the closed shells
>> behave diamagnetic as they should.
>> I doubt that this will work for all materials as in most cases the
>> induced moment will be just to low to decide even if you use brute force
>> (very high field, very much k-points etc.)
>> If a ferro- or other "magnetic" solution is close, then the application
>> of the field may break the symmetry in such a way that you run into this
>> state instead of staying in the paramagnetic state.
>> Diamagnetism will probably not bee seen in Semiconductors.
>> You may try semimetallic graphite which is a "strong" diamagnet to see
>> whether it is possible to see any antiparallel allignment of induced
>> magnetic moments.
>>
>> I did not further check, maybe there are some codes available to
>> calculate the suscebtibility of para- or diamagnetic materials.
>>
>>
>> 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
>> karima Physique [physique.karima at gmail.com]
>> Gesendet: Montag, 8. Mai 2017 14:48
>> An: A Mailing list for WIEN2k users
>> Betreff: Re: [Wien] paramagnetic or diamagnetic
>>
>> Thank you very much for your answer
>> I started a calculation in several magnetic phases (non-magnetic,
>> ferromagnetic and antiferromagnetic) and I found that the non-magnetic
>> phase is the most stable. so how can I know if the studied  material is a
>> paramagnetic or diamagnetic material?
>> Thank you in advance
>>
>> 2017-05-08 8:06 GMT+02:00 Fecher, Gerhard <fecher at uni-mainz.de<mailto:fe
>> cher at uni-mainz.de>>:
>> What distinguishes a paramagnetic from a diamagnetic material ?
>> a) at zero magnetic field the induced magnetic moment is zero for both
>> b) at external magnetic field the induced magnetiuc moment is parallel /
>> antiparallel to the applied field.
>> c) both is true
>> d) none is true
>>
>> There was already a discussion about paramagnetism, see
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at
>> /msg15029.html
>>
>> 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<mailto:wien-bounces
>> @zeus.theochem.tuwien.ac.at>] im Auftrag von karima Physique [
>> physique.karima at gmail.com<mailto:physique.karima at gmail.com>]
>> Gesendet: Samstag, 6. Mai 2017 01:50
>> An: A Mailing list for WIEN2k users
>> Betreff: [Wien] paramagnetic or diamagnetic
>>
>> Dear Wien2k users:
>>
>> How I can know if the material is paramagnetic or diamagnetic with a
>> calculation.?
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>>
> --
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
> Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
> WWW: http://www.imc.tuwien.ac.at/tc_blaha------------------------
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