<div dir="ltr"><div><div><div><div><div>Hi all,<br></div>I am not calculating MR directly from WIEN2K, what I want to do is to get<br></div>a band structure at particular direction of magnetic field (say 3T at different angle 20, 40, 60, 80 and so on...) with current.<br></div>I shall use that band structure in DMFT to get resistance. So I asked how to apply magnetic field and electric field in WIEN2K<br></div>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.<br><br></div>I am not using boltztrap.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, May 23, 2018 at 10:57 AM, Karel Vyborny <span dir="ltr"><<a href="mailto:vybornyk@fzu.cz" target="_blank">vybornyk@fzu.cz</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Gavin,<br>
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.<br>
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.<br>
<br>
Anyway, Sudipta may want to be a little more specific about the object of study so as to get more of advice...<br>
<br>
Cheers,<br>
<br>
Karel<br>
<br>
<br>
<br>
PS: a bit self-advertising... Look at PRB 80, 165204 or<br>
<br>
<a href="https://arxiv.org/abs/0906.3151" rel="noreferrer" target="_blank">https://arxiv.org/abs/0906.315<wbr>1</a><br>
<br>
Fig. 1 is a graphical summary of how AMR may arise.<br>
<br>
--- x ---<br>
dr. Karel Vyborny<br>
Fyzikalni ustav AV CR, v.v.i.<br>
Cukrovarnicka 10<br>
Praha 6, CZ-16253<br>
tel: +420220318459<br>
<br>
<br>
On Tue, 22 May 2018, Gavin Abo wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Someone else may know differently, but as far as I know, WIEN2k has no<br>
function for calculating MR (magnetoresistance).<br>
<br>
I don't know the details of what your are trying to do exactly, but it may<br>
be that WIEN2k's magnetic field doesn't do what you think it does.<br>
<br>
Refer to the previous posts:<br>
<br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16108.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg16108.html</a><br>
<br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg11093.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg11093.html</a><br>
<br>
For example a VSM with Magneto Resistance option can only apply up to 3.5 T<br>
[ <a href="http://www.microsense.net/products-vsm.htm" rel="noreferrer" target="_blank">http://www.microsense.net/prod<wbr>ucts-vsm.htm</a> ]. Some of the best<br>
electromagnets in the world cannot apply too much higher magnetic fields<br>
than that. In the above post, at least a 10 T magnetic field has to be<br>
applied to even see an effect. However, I don't know how to properly<br>
explain that. My guess is that might be because WIEN2k's magnetic field is<br>
an atomic local field instead of a micro/macro uniform field.<br>
<br>
Do you maybe need a spin-polarized current in a spin-torque based<br>
micromagnetic simulator like oommf [ <a href="https://math.nist.gov/oommf/" rel="noreferrer" target="_blank">https://math.nist.gov/oommf/</a> , <br>
<a href="http://layer.uci.agh.edu.pl/M.Frankowski/download.html" rel="noreferrer" target="_blank">http://layer.uci.agh.edu.pl/M.<wbr>Frankowski/download.html</a> ], LLG Micromagnetic<br>
Simulator [<a href="http://llgmicro.home.mindspring.com/DataRep/HysAndMRLoops/HysAndMrFrame.htm" rel="noreferrer" target="_blank">http://llgmicro.home.mindspri<wbr>ng.com/DataRep/HysAndMRLoops/<wbr>HysAndMrFrame.htm</a><br>
], or VAMPIRE [ <a href="http://vampire.york.ac.uk/research/" rel="noreferrer" target="_blank">http://vampire.york.ac.uk/rese<wbr>arch/</a> ]?<br>
<br>
Or are you trying to calculate magnetic anisotropy energy (MAE) [<br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09408.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg09408.html</a><br>
]?<br>
<br>
I never figured out how to do it, but tunneling current is a function of<br>
density of states, fermi functions, and tunneling probability [<br>
<a href="http://dx.doi.org/10.9756/BIJPSIC.3129" rel="noreferrer" target="_blank">http://dx.doi.org/10.9756/BIJP<wbr>SIC.3129</a> ]. So I thought there might be a<br>
slight possibility to extract data from WIEN2k and post calculate that.<br>
<br>
Hope that can help and good luck.<br>
<br>
On 5/22/2018 9:21 AM, sudipta wrote:<br>
I want to calculate anisotropy in magnetoresistance. I want to<br>
to apply both magnetic field and current at same time to a<br>
system. In wien2k through inorb<br>
I can apply magnetic field, but how to give current at the same time.<span class="HOEnZb"><font color="#888888"><br>
<br>
--<br>
Sudipta koley<br>
Department of Physics<br>
IIT KHARAGPUR<br>
<br>
<br>
<br>
</font></span></blockquote>
</blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Sudipta koley<br>Department of Physics<br>IIT KHARAGPUR</div>
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