dear Kun Tao the 3D visualization of the up-down charge density in the different cells you have studied should probably clarify to you what the system is trying to teach you.
stefano On 03/13/2013 10:36 PM, ?? wrote: > I try to force two Gd atom into ferromagnetic with following parameters: > > nat= 2, ntyp=2, > starting_magnetization(1)=1.0, > starting_magnetization(2)=1.0, > > ATOMIC_SPECIES > Gd1 1.0 Gd.GGA-PBE-paw.UPF > Gd2 1.0 Gd.GGA-PBE-paw.UPF > ATOMIC_POSITIONS {crystal} > Gd1 0.33333333 0.66666667 0.25 > Gd2 0.66666667 0.33333333 0.75 > > And I got the following results: > > total magnetization = 7.55 Bohr mag/cell > absolute magnetization = 8.02 Bohr mag/cell > > In this case, even the "absolute magnetization" is wrong. And the > magnetic moments on two atoms are 0.47, 7.08, respectively, which are > are away from the experimental results 7.8 for each atom. > > I do not know the reason, perhaps there is a small bug in the code for > 4f elements or due to some incorrect parameters in my input file. Any > suggestion is appreciated! > > With regards, > Kun Tao > > On 13 March 2013 12:35, mohnish pandey <mohnish.iitk at gmail.com> wrote: >> 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. >> >> >> On Wed, Mar 13, 2013 at 9:03 PM, ?? <taokun76 at gmail.com> wrote: >>> Thank you for your suggestions. When I set two atoms in the unit cell >>> to be antiferromagnetic, the "total magnetization" is nearly zero, and >>> the "absolute magnetization" is about 14.67. And the magnetic moment >>> for two atoms are about 7.16 and -7.18, which is more or less >>> acceptable. >>> >>> Now, the question is that why "total magnetization" and "absolute >>> magnetization" differs so much if I want to force two atoms into a >>> ferromagnetic configuration. >>> >>> Any suggestions? Thanks! >>> >>> With regards, >>> Kun Tao >>> >>> >>> On 13 March 2013 11:14, Andrei Malashevich <andrei.malashevich at yale.edu> >>> wrote: >>>> If you want to model antiferromagnetic structure, you should define two >>>> types of atoms, Gd1 and Gd2. >>>> Change ntyp to 2. Use, e.g., >>>> starting_magnetization(1)=1.0 >>>> starting_magnetization(2)=-1.0 >>>> >>>> ATOMIC_SPECIES >>>> Gd1 1.0 Gd.GGA-PBE-paw.UPF >>>> Gd2 1.0 Gd.GGA-PBE-paw.UPF >>>> ATOMIC_POSITIONS {crystal} >>>> Gd1 0.33333333 0.66666667 0.25 >>>> Gd2 0.66666667 0.33333333 0.75 >>>> >>>> >>>> On Wed, Mar 13, 2013 at 11:05 AM, ?? <taokun76 at gmail.com> wrote: >>>>> Hi, >>>>> >>>>> Yes, the bulk Gd without Hubbard U is antiferromagnetic. If I set the >>>>> two atoms in the unit cell to be antiferromagnetic, the "total >>>>> magnetization" should be equal to zero, and the "absolute >>>>> magnetization" is what I have gotten. Now, however, the "total >>>>> magnetization" is not zero. Could you give me some suggestions? >>>>> Thanks! >>>>> >>>>> With regards, >>>>> Kun Tao >>>>> >>>>> On 13 March 2013 10:48, Stefano de Gironcoli <degironc at sissa.it> wrote: >>>>>> are you sure you are defining the correct magnetic structure ? >>>>>> is Gd maybe antiferromagnetic ? >>>>>> stefano >>>>>> >>>>>> On 03/13/2013 03:19 PM, ?? wrote: >>>>>>> Dear everyone, >>>>>>> >>>>>>> I want to calculate the magnetic properties of bulk Gd whose >>>>>>> magnetic >>>>>>> moment is about 8 Bohr magneto/atom. Usually, in the output file >>>>>>> values of "total magnetization" and "absolute magnetization" should >>>>>>> be >>>>>>> nearly the same. However, in my output file, I found a big >>>>>>> difference >>>>>>> between them as following: >>>>>>> >>>>>>> total magnetization = 8.00 Bohr mag/cell >>>>>>> absolute magnetization = 15.72 Bohr mag/cell >>>>>>> >>>>>>> The good news is that the "absolute magnetization" is close to the >>>>>>> experimental results (7.86 Bohr mag/atom), the bad news is that the >>>>>>> "total magnetization" is wrong. Moreover, when I try to calculate >>>>>>> the >>>>>>> magnetic moment on each atom with projwfc.x program, I got about 4.1 >>>>>>> Bohr mag/atom. >>>>>>> >>>>>>> Could you give me some suggestions? Any advice are appreciated, >>>>>>> thanks! >>>>>>> >>>>>>> Regards, >>>>>>> Kun Tao >>>>>>> >>>>>>> >>>>>>> Attached below is the input file: >>>>>>> >>>>>>> &control >>>>>>> calculation='scf' >>>>>>> restart_mode='from_scratch', >>>>>>> prefix='Gd', >>>>>>> pseudo_dir = './' >>>>>>> outdir='./', >>>>>>> / >>>>>>> &system >>>>>>> ibrav= 4, celldm(1)= 6.96, celldm(3)= 1.59, >>>>>>> nat= 2, ntyp=1, >>>>>>> nspin = 2, >>>>>>> starting_magnetization(1)=1.0, >>>>>>> ecutwfc=55.0, >>>>>>> ecutrho=220.0, >>>>>>> occupations ='smearing', >>>>>>> smearing ='gauss', >>>>>>> degauss = 0.01, >>>>>>> / >>>>>>> &electrons >>>>>>> diagonalization='david', >>>>>>> mixing_beta = 0.3, >>>>>>> conv_thr = 1.0d-8, >>>>>>> / >>>>>>> ATOMIC_SPECIES >>>>>>> Gd 1.0 Gd.GGA-PBE-paw.UPF >>>>>>> ATOMIC_POSITIONS {crystal} >>>>>>> Gd 0.33333333 0.66666667 0.25 >>>>>>> Gd 0.66666667 0.33333333 0.75 >>>>>>> K_POINTS {automatic} >>>>>>> 4 4 4 0 0 0 >>>>>>> _______________________________________________ >>>>>>> Pw_forum mailing list >>>>>>> Pw_forum at pwscf.org >>>>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>>>> _______________________________________________ >>>>>> Pw_forum mailing list >>>>>> Pw_forum at pwscf.org >>>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>>> _______________________________________________ >>>>> Pw_forum mailing list >>>>> Pw_forum at pwscf.org >>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>> >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> Pw_forum at pwscf.org >>>> http://pwscf.org/mailman/listinfo/pw_forum >>> _______________________________________________ >>> Pw_forum mailing list >>> Pw_forum at pwscf.org >>> http://pwscf.org/mailman/listinfo/pw_forum >> >> >> >> -- >> Regards, >> MOHNISH, >> ----------------------------------------------------------------- >> Mohnish Pandey, >> PhD Student, >> Center for Atomic Scale Materials Design, >> Department of Physics, >> Technical University of Denmark >> ----------------------------------------------------------------- >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://pwscf.org/mailman/listinfo/pw_forum > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum