Did you try using different initial spin configurations? If your interested in FM ground state then may be you should try initial magnetic configuration as FM. e.g. +1, +1 for both.<br><br><div class="gmail_quote">On Wed, Mar 13, 2013 at 9:03 PM, µb³³ <span dir="ltr"><<a href="mailto:taokun76@gmail.com" target="_blank">taokun76@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thank you for your suggestions. When I set two atoms in the unit cell<br>
to be antiferromagnetic, the "total magnetization" is nearly zero, and<br>
the "absolute magnetization" is about 14.67. And the magnetic moment<br>
for two atoms are about 7.16 and -7.18, which is more or less<br>
acceptable.<br>
<br>
Now, the question is that why "total magnetization" and "absolute<br>
magnetization" differs so much if I want to force two atoms into a<br>
ferromagnetic configuration.<br>
<br>
Any suggestions? Thanks!<br>
<br>
With regards,<br>
Kun Tao<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
On 13 March 2013 11:14, Andrei Malashevich <<a href="mailto:andrei.malashevich@yale.edu">andrei.malashevich@yale.edu</a>> wrote:<br>
> If you want to model antiferromagnetic structure, you should define two<br>
> types of atoms, Gd1 and Gd2.<br>
> Change ntyp to 2. Use, e.g.,<br>
> starting_magnetization(1)=1.0<br>
> starting_magnetization(2)=-1.0<br>
><br>
> ATOMIC_SPECIES<br>
> Gd1 1.0 Gd.GGA-PBE-paw.UPF<br>
> Gd2 1.0 Gd.GGA-PBE-paw.UPF<br>
> ATOMIC_POSITIONS {crystal}<br>
> Gd1 0.33333333 0.66666667 0.25<br>
> Gd2 0.66666667 0.33333333 0.75<br>
><br>
><br>
> On Wed, Mar 13, 2013 at 11:05 AM, µb³³ <<a href="mailto:taokun76@gmail.com">taokun76@gmail.com</a>> wrote:<br>
>><br>
>> Hi,<br>
>><br>
>> Yes, the bulk Gd without Hubbard U is antiferromagnetic. If I set the<br>
>> two atoms in the unit cell to be antiferromagnetic, the "total<br>
>> magnetization" should be equal to zero, and the "absolute<br>
>> magnetization" is what I have gotten. Now, however, the "total<br>
>> magnetization" is not zero. Could you give me some suggestions?<br>
>> Thanks!<br>
>><br>
>> With regards,<br>
>> Kun Tao<br>
>><br>
>> On 13 March 2013 10:48, Stefano de Gironcoli <<a href="mailto:degironc@sissa.it">degironc@sissa.it</a>> wrote:<br>
>> > are you sure you are defining the correct magnetic structure ?<br>
>> > is Gd maybe antiferromagnetic ?<br>
>> > stefano<br>
>> ><br>
>> > On 03/13/2013 03:19 PM, µb³³ wrote:<br>
>> >> Dear everyone,<br>
>> >><br>
>> >> I want to calculate the magnetic properties of bulk Gd whose magnetic<br>
>> >> moment is about 8 Bohr magneto/atom. Usually, in the output file<br>
>> >> values of "total magnetization" and "absolute magnetization" should be<br>
>> >> nearly the same. However, in my output file, I found a big difference<br>
>> >> between them as following:<br>
>> >><br>
>> >> total magnetization = 8.00 Bohr mag/cell<br>
>> >> absolute magnetization = 15.72 Bohr mag/cell<br>
>> >><br>
>> >> The good news is that the "absolute magnetization" is close to the<br>
>> >> experimental results (7.86 Bohr mag/atom), the bad news is that the<br>
>> >> "total magnetization" is wrong. Moreover, when I try to calculate the<br>
>> >> magnetic moment on each atom with projwfc.x program, I got about 4.1<br>
>> >> Bohr mag/atom.<br>
>> >><br>
>> >> Could you give me some suggestions? Any advice are appreciated, thanks!<br>
>> >><br>
>> >> Regards,<br>
>> >> Kun Tao<br>
>> >><br>
>> >><br>
>> >> Attached below is the input file:<br>
>> >><br>
>> >> &control<br>
>> >> calculation='scf'<br>
>> >> restart_mode='from_scratch',<br>
>> >> prefix='Gd',<br>
>> >> pseudo_dir = './'<br>
>> >> outdir='./',<br>
>> >> /<br>
>> >> &system<br>
>> >> ibrav= 4, celldm(1)= 6.96, celldm(3)= 1.59,<br>
>> >> nat= 2, ntyp=1,<br>
>> >> nspin = 2,<br>
>> >> starting_magnetization(1)=1.0,<br>
>> >> ecutwfc=55.0,<br>
>> >> ecutrho=220.0,<br>
>> >> occupations ='smearing',<br>
>> >> smearing ='gauss',<br>
>> >> degauss = 0.01,<br>
>> >> /<br>
>> >> &electrons<br>
>> >> diagonalization='david',<br>
>> >> mixing_beta = 0.3,<br>
>> >> conv_thr = 1.0d-8,<br>
>> >> /<br>
>> >> ATOMIC_SPECIES<br>
>> >> Gd 1.0 Gd.GGA-PBE-paw.UPF<br>
>> >> ATOMIC_POSITIONS {crystal}<br>
>> >> Gd 0.33333333 0.66666667 0.25<br>
>> >> Gd 0.66666667 0.33333333 0.75<br>
>> >> K_POINTS {automatic}<br>
>> >> 4 4 4 0 0 0<br>
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Mohnish Pandey,<br>PhD Student,<br>Center for Atomic Scale Materials Design,<br>Department of Physics,<br>Technical University of Denmark<br><div>-----------------------------------------------------------------</div>