Thank you for this hint Dr. Rebaza. You are absolutely right using the total_magnetization flag for this system. Neither non-collinear magnetization nor spin-orbit coupling is required for my calculations, therefore we can set nspin to 2 and fix only the magnitude of the magnetization, because without spin orbit, no direction is preferred.
The &cell and &ions namelists are simply set in my 'master template file' I use for all calculations on a system. In case of a simple scf calculation, these cards are ignored anyways...so I just keep them in the input file. Thanks again for the paper, they did exactly what I needed to know :) In case anyone is interested in more information on that stoner stuff, this is the book you want to have a look at: http://link.springer.com/book/10.1007%2F978-3-642-82499-9 Best regards from Germany, Rene Wirnata Am 7/24/2014 12:00 AM, schrieb Arles V. Gil Rebaza: > Hi Rene Wirnata, I think that you must to obtaind the total energy > (Et) vs total magnetic moment (MT) and fot with a curve of 4to order > (Ax^4 + Bx^2+C). The coeficient of the cuadratic term (B) is related > with the stones parameter. So, to get this curve you must to do scf > calculations for each MT value using fixed spin calculations (use > "total_magnetization" in QE). > Maybe this paper could help > you: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.74.014416 > > In your input file, if you are doing SCF calculation, why you use > &cell > press_conv_thr = 0.1 > these tag is for vc-relax calculations > > why ... > &electrons > mixing_mode='TF' > try with the default setting "plain" > > nspin = 4 .... are you performing non-collinear calculations.?? > > I hope I've helped > > Best. > > Dr. Arles V. Gil Rebaza > Instituto de F?sica La Plata > Argentina. > > > > > > 2014-07-23 11:44 GMT-03:00 Rene Wirnata <renewirnata at gmx.de > <mailto:renewirnata at gmx.de>>: > > Hi @ all! > > Unfortunately I couldn't find anything on this topic with google, > so I have to ask here: > > Currently, I try to test the stoner criterion for the Al5Fe2 > system and therefore I set > */"constrained_magnetization = 'total', fixed_magnetization(3) = > i, lambda = 1.d0"/* > where i = {0.0 .. 2.2}. This setup will first of all tell me in > the output file that I have to > set *nspin = 4*, setting it to sth. else won't work, I already > tested. Now the problem is > none of these calculations will converge doing max. 100 > iterations. Even if I set > *lambda =**0.1*, there's no big change as you can see in the > output files. > > Further, the documentation tells me: > a) for LDA potentials use *tot_magnetization*, --> mine is GGA, so > stay with *contrained_mag**...* > b) if I used *tot_magnetization* then I shouldn't use > *starting_magnetization*, so maybe this > could help? But to what number should I set it, because for every > atom in my cell it will > become different during the iterations. > > Unfortunately, no one in my institut ever did such calculations > before and I am > myself still a total beginner with pwscf, so pls excuse if the > question is stupid :). > > Thanks a lot in advance! > > Best regards from Germany, > > Rene Wirnata > > > -- > Attachements see here: > https://www.dropbox.com/sh/zxr7phpxdngo0zl/AABWJEqMog7eawxvTec9FH7pa > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > http://pwscf.org/mailman/listinfo/pw_forum > > > > > -- > ###---------> Arles V. <---------### > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140729/8d47bd96/attachment.html -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 553 bytes Desc: OpenPGP digital signature Url : http://pwscf.org/pipermail/pw_forum/attachments/20140729/8d47bd96/attachment.bin
