<div>Dear Ciao,</div>
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<div>Thank you for your reply. Your advice was very helpful for me to understand.</div>
<div>I have used 10,000 k-points for MnAl calculation. 372,248 is 37 times larger than the k-points that I used.</div>
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<div>And I did not mean the experimental RMT. I meant changing RMT to fit an experimental K value.</div>
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<div>So, is it a good number of k-points (~300,000) for 2 to 4 atoms phase to calculated K?</div>
<div>And should I do the relaxation for magnetic materials? Somebody say that we do not need it for magnetic materials; simply take an experimental lattice constant.</div>
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<div>All my best,</div>
<div>Jihoon Park</div>
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<div>To find the magntic anisotropy is a "brute force" job (see chapter 4.6.4 of the textbook of J Kübler, Theory of itinerant electron magnetism),<br>that means you need really many k-points<br>(The question is what is "many" ? As answer from experience I would say: If you think you have enough then just take a lot more ! <br>
There is an example in Küblers book where Halilov used 372 248 k-points in the full Brillouinn zone.)<br>So how many k-points did you use ?<br><br>There is another thing one should keep in mind, some experimental values may be influenced by the shape anisotropy<br>
of the sample that was used (unfortunately in many experimental work not enough information is given).<br>MnAl has a rich binary phase diagramm, are you shure that the experimental values are for a single phase sample ?<br>
<br>What do you mean with experimental RMT ?<br>There is some older LEED theory where the muffin tin radii were calculated from the energy dependence of<br>low energy electron diffraction pattern. I guess that these have nothing to do with the RMT you set in Wien2k.<br>
<br><br>Ciao<br>Gerhard<br><br>====================================<br>Dr. Gerhard H. Fecher<br>Institut of Inorganic and Analytical Chemistry<br>Johannes Gutenberg - University<br>55099 Mainz<br>________________________________________<br>
Von: <a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">wien-bounces at zeus.theochem.tuwien.ac.at</a> [<a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">wien-bounces at zeus.theochem.tuwien.ac.at</a>]&quot; im Auftrag von &quot;Jihoon Park [<a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">jpark61 at crimson.ua.edu</a>]<br>
Gesendet: Samstag, 4. Juni 2011 04:37<br>Bis: <a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">wien at zeus.theochem.tuwien.ac.at</a><br>Betreff: [Wien] Magnetic material relaxation, RMT, MAE calculations<br>
<br>Dear users,<br><br><br>I am really wondering if we have to "relax" structure everytime when calculating magnetic materials.<br>When relaxed, the magnetic properties, especially K value, become too far from experimental data; K value calculated from not relaxed structure is also far from the experimental one.<br>
<br>I tried force theorem as well, but that is still far from the experimental data too.<br><br>Everytime my calculated K value is reversed.<br>For example, energies for <001> and <100> are compared and used to calculate K.<br>
But I do not understand why the energy for <100> is lower than that of <001>.<br>Experimentally, <001> is stable for MnAl.<br><br><br>And another qeustion is about RMT.<br>Is it okay to change RMT to fit experimental data?<br>
I tried several times to fit experimental one, but still question myself if that is okay.<br><br></div>