ABINIT Discussion Forums

Im doing some calculations on magnetic properties of heusler alloy Co2MnAl. The magnetic moment i got is 6.88 instead of 4.03. My input is shown below


#Co2MnAl :

#ndtset 10

#Definition of the k-point grids
kptopt 1

nshiftk 4
shiftk 0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5

ngkpt 6 6 6

getwfk -1



#Definition of the planewave basis set
ecut 75

#Definition of the SCF procedure
nstep 100
toldfe 1.0d-7
diemac 12.0
iscf 7


#optimization parameters
#optcell 1
#ionmov 3
#ntime 10
#dilatmx 1.05
#ecutsm 0.5
#strfact 100
#tolmxf 5.0d-5

# definition of unit cell
acell 3*10.9
chksymbreak 0
chkprim 0
rprim 0 0.5 0.5
0.5 0 0.5
0.5 0.5 0


#spin polarized calc
nsppol 2
nspinor 1
nspden 2
spinat 0.0 0.0 1.0
0.0 0.0 1.0
0.0 0.0 1.0
0.0 0.0 1.0



znucl 27 25 13
nband 36
ntypat 3
natom 4
npsp 3
typat 1 2 1 3
xred 0.00 0.00 0.00 #Co
0.25 0.25 0.25 #Mn
0.50 0.50 0.50 #Co
0.75 0.75 0.75 #Al


occopt 3
tsmear 0.01
ixc 11

I need help to get correct magnetic moment.
Thanks

PLEASE HELP

Dear Bamgbose,
To be sure before going further, how did you extract the magnetization because there is two ways:
1) from prtdenpsh=1 that prints the magnetization in spheres around each atoms
2) the total one from the integration of density_up minus density_dn and printed after "Magnetization (spin up - spin down) [el/Bohr^3]" in the output?
In any case it would be nice if you give us the output of 1) and 2).
Otherwise I would ask if you did your convergence tests with respect to the k-points because for a metal 6x6x6 might be too small for such cell size.
A second remark is if DFT+U would be preferable in this system with Mn and Co atoms?
Best wishes,
Eric

Dear Eric, thanks for ur reply. I attached my out file below

Dear Bamgbose,
OK, the magnetization you report is the exact total one.
However, can you rerun the calculation by setting up the input variable
prtdensph 1
to get the integrated magnetization around each atom in order to determine how is the magnetic moment on each atom?
In the meantime, did you test whether your calculations are converged with respect to the k-points grid?
All the best,
Eric

Dear Eric,
Thanks for correction to my input file. Inclusion of prtdensph 1 gave me magnetic moment of each atom, but my pc cannot run high k-point grid which is needed for heusler alloys. Eric can u collaborate with me and get supercomputer access for me to do this calculations. Thanks.
-Bamgbose