[Wien] Results of ferromagnetic state is same as ferrimagnetic state?

[Stefaan Cottenier]

As your results for the magnetic moments show, you obtained twice the  
ferrimagnetic solution. That frequently happens, it is not because you  
specify some starting configuration in case.inst that it will end up  
in the same configuartion after the scf cycle. If you really need the  
ferromagnetic solution, you can try a FSM (fixed spin moment)  
calculation, specifying a magnetic moment in the unit cell that is the  
sum of all absolute values of the ferrimagnetic moments (= somewhat  
larger than 4.0). Or you can turn to the non-collinear code wienncm  
(requires a different license and installation), where you can specify  
and keep frozen any configuration you want.

Stefaan


> Dear WIEN2k users:
>   I am pullzed of my recent calculation results. I did a   
> ferromagnetic state Sr2FeMoO6 calculation and a ferrimagnetic state   
> Sr2FeMoO6 calculation to get energy difference between them, but I   
> find the results(total energy and magnetic moments) are almost   
> equal. I don't understand why this happens, in my opinion, the two   
> different states should have a evident energy difference. Could spin  
>  up electron provide spin down magnetic moment? Below is the detail:
>
> ferromagnetic state
> case.inst:
> -----------------------------------------
> Fe
> Ar 3 5
> 3, 2,2.0  N
> 3, 2,2.0  N
> 3,-3,2.5  N
> 3,-3,0.0  N
> 4,-1,1.0  N
> 4,-1,0.5  N
> Mo
> Kr 3 5
> 4, 2,2.0  N
> 4, 2,1.0  N
> 4,-3,2.0  N
> 4,-3,0.0  N
> 5,-1,1.0  N
> 5,-1,0.0  N
> Sr
> Kr 1 5
> 5,-1,1.0  N
> 5,-1,1.0  N
> O
> He 3 5
> 2,-1,1.0  N
> 2,-1,1.0  N
> 2, 1,1.0  N
> 2, 1,1.0  N
> 2,-2,1.0  N
> 2,-2,1.0  N
> ------------------------------------------
> Results:
> :ENE  : ********** TOTAL ENERGY IN Ry =       -24235.219288
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL =    0.01427
> :MMI001: MAGNETIC MOMENT IN SPHERE   1    =    3.77423  (Fe)
> :MMI002: MAGNETIC MOMENT IN SPHERE   2    =   -0.25870  (Mo)
> :MMI003: MAGNETIC MOMENT IN SPHERE   3    =   -0.00471  (Sr)
> :MMI004: MAGNETIC MOMENT IN SPHERE   4    =    0.08151  (O)
> :MMTOT: TOTAL MAGNETIC MOMENT IN CELL   =    4.00942
>
> ferrimagnetic state
> case.inst:
> ------------------------------
> Fe
> Ar 3 5
> 3, 2,2.0  N
> 3, 2,2.0  N
> 3,-3,2.5  N
> 3,-3,0.0  N
> 4,-1,1.0  N
> 4,-1,0.5  N
> Mo
> Kr 3 5
> 4, 2,1.0  N  <----------- spin flipped
> 4, 2,2.0  N
> 4,-3,0.0  N  <----------- spin flipped
> 4,-3,2.0  N
> 5,-1,0.0  N  <----------- spin flipped
> 5,-1,1.0  N
> Sr
> Kr 1 5
> 5,-1,1.0  N
> 5,-1,1.0  N
> O
> He 3 5
> 2,-1,1.0  N
> 2,-1,1.0  N
> 2, 1,1.0  N
> 2, 1,1.0  N
> 2,-2,1.0  N
> 2,-2,1.0  N
> ----------------------------------
> Results:
> :ENE  : ********** TOTAL ENERGY IN Ry =       -24235.219248
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL =    0.00605
> :MMI001: MAGNETIC MOMENT IN SPHERE   1    =    3.77188  (Fe)
> :MMI002: MAGNETIC MOMENT IN SPHERE   2    =   -0.26145  (Mo)
> :MMI003: MAGNETIC MOMENT IN SPHERE   3    =   -0.00538  (Sr)
> :MMI004: MAGNETIC MOMENT IN SPHERE   4    =    0.08241  (O)
> :MMTOT: TOTAL MAGNETIC MOMENT IN CELL   =    4.00019
>
>
> Best regards,
> Jinyun Li



-- 
Stefaan Cottenier
Instituut voor Kern- en Stralingsfysica
K.U.Leuven
Celestijnenlaan 200 D
B-3001 Leuven (Belgium)

tel: + 32 16 32 71 45
fax: + 32 16 32 79 85
e-mail: stefaan.cottenier at fys.kuleuven.be


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