[Wien] (no subject)

[sudipta]

Hi all,
I am not calculating MR directly from WIEN2K, what I want to do is to get
a band structure at particular direction of magnetic field (say 3T at
different angle 20, 40, 60, 80 and so on...) with current.
I shall use that band structure in DMFT to get resistance. So I asked how
to apply magnetic field and electric field in WIEN2K
at different direction at a time. With inorb input we can apply magnetic
field at certain direction but how to apply electric field at the same time.

I am not using boltztrap.

On Wed, May 23, 2018 at 10:57 AM, Karel Vyborny <vybornyk at fzu.cz> wrote:

> Hi Gavin,
> let me add to what you write and also correct one thing you mention.
> First, you are right that WIEN2k is not very useful for calculating MR.
> Magnetoresistances make a large (and diverse) field, so one should be more
> specific about what exactly is to be calculated. But if I consider
> anisotropic magnetoresistance (AMR), for example, you need band structure
> and a model for scattering to get a theoretical prediction. The former can
> be obtained by WIEN2k but not the latter (at least not in a straightforward
> manner). In boltztrap, they get away with "constant Gamma" (one
> phenomenological relaxation time) for example and this, most likely, misses
> the relevant physics of AMR.
>  Regarding magnetic field, I'd call ~30 T the state-of-the art: for you,
> the nearest option would be Florida (NHMFL), similar European facilities
> are in France (Grenoble) and the Netherlands.
>
> Anyway, Sudipta may want to be a little more specific about the object of
> study so as to get more of advice...
>
> Cheers,
>
> Karel
>
>
>
> PS: a bit self-advertising... Look at PRB 80, 165204 or
>
> https://arxiv.org/abs/0906.3151
>
> Fig. 1 is a graphical summary of how AMR may arise.
>
> --- x ---
> dr. Karel Vyborny
> Fyzikalni ustav AV CR, v.v.i.
> Cukrovarnicka 10
> Praha 6, CZ-16253
> tel: +420220318459
>
>
> On Tue, 22 May 2018, Gavin Abo wrote:
>
>
>> Someone else may know differently, but as far as I know, WIEN2k has no
>> function for calculating MR (magnetoresistance).
>>
>> I don't know the details of what your are trying to do exactly, but it may
>> be that WIEN2k's magnetic field doesn't do what you think it does.
>>
>> Refer to the previous posts:
>>
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at
>> /msg16108.html
>>
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at
>> /msg11093.html
>>
>> For example a VSM with Magneto Resistance option can only apply up to 3.5
>> T
>> [ http://www.microsense.net/products-vsm.htm ].  Some of the best
>> electromagnets in the world cannot apply too much higher magnetic fields
>> than that.  In the above post, at least a 10 T magnetic field has to be
>> applied to even see an effect.  However, I don't know how to properly
>> explain that.  My guess is that might be because WIEN2k's magnetic field
>> is
>> an atomic local field instead of a micro/macro uniform field.
>>
>> Do you maybe need a spin-polarized current in a spin-torque based
>> micromagnetic simulator like oommf [ https://math.nist.gov/oommf/ ,
>> http://layer.uci.agh.edu.pl/M.Frankowski/download.html ], LLG
>> Micromagnetic
>> Simulator [http://llgmicro.home.mindspring.com/DataRep/HysAndMRLoops/
>> HysAndMrFrame.htm
>> ], or VAMPIRE [ http://vampire.york.ac.uk/research/ ]?
>>
>> Or are you trying to calculate magnetic anisotropy energy (MAE) [
>> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at
>> /msg09408.html
>> ]?
>>
>> I never figured out how to do it, but tunneling current is a function of
>> density of states, fermi functions, and tunneling probability [
>> http://dx.doi.org/10.9756/BIJPSIC.3129 ].  So I thought there might be a
>> slight possibility to extract data from WIEN2k and post calculate that.
>>
>> Hope that can help and good luck.
>>
>> On 5/22/2018 9:21 AM, sudipta wrote:
>>       I want to calculate anisotropy in magnetoresistance. I want to
>>       to apply both magnetic field and current at same time to a
>>       system. In wien2k through inorb
>> I can apply magnetic field, but how to give current at the same time.
>>
>> --
>> Sudipta koley
>> Department of Physics
>> IIT KHARAGPUR
>>
>>
>>
>>


-- 
Sudipta koley
Department of Physics
IIT KHARAGPUR
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