[Wien] exchange coupling constants calculations

[Linux PC]

Thank you Xavier and Guillaume.

One more small question. If I have ferromagnetic system (experimental data), 
calculated total energy in spinpolarized ferromagnetic system (let's call it 
E(SP)) then in order to get E(FM) from your formula, I have to calculate total 
energy of a non-spinpolarized system (E(NSP)), then I can calculate E(FM) like 
E(FM) = E(SP)-E(NSP). Am I right?

Thank you!

Date: Wed, 18 May 2011 14:11:18 +0200
From: xavier.rocquefe...@cnrs-imn.fr
To: wien at zeus.theochem.tuwien.ac.at
Subject: Re: [Wien] exchange coupling constants calculations



  



  
  
Dear Vincent,



The rule is quite simple. Let's take the example of a monoatomic
linear chain. 

To obtain the J parameter coupling two adjacent magnetic centers,
you simply have to do 2 calculations:



- one with the ferromagnetic order: FM

- one with the antiferromagnetic order: AFM



You will then obtain two total energies, i.e. E(FM) and E(AFM). 



Considering an Heisenberg Hamiltonian, you have:



E(FM) = N?/4 * (-J)



and 



E(AFM) = N?/4 * (+J)



Then E(AFM) - E(FM) = N?/4 * (2*J) = N?/2 * J



where N is the number of unpaired electrons on the magnetic center.




For example, for N = 1:



J = 2 * (E(AFM) - E(FM))



The present example is very simple and you could imagine that for
more complex structures it will be more difficult to realize a
mapping analysis. Then the idea is:

- to use more magnetic orders than unknown J parameters

- to do a least-square procedure to find the J values ...



Here is and example of calculations I did with Peter and Karlheinz
on CuO:



http://iopscience.iop.org/0953-8984/22/4/045502



If you do not have access to the paper, I could send it to you. 



Regards



Xavier











Le 18/05/2011 12:31, Linux PC a ?crit :

  
  Dear Xavier,

  

  Thank you very much for the answer! I actually was looking through
  the manual before, unfortunately, did not succeed in finding any
  information on exchange interactions. Would you know, or may be
  other users, if any practical manual exists for calculating of J.

  

  Thank you!

  Vincent

  

  > Date: Wed, 18 May 2011 07:24:52 +0200

  > From: Xavier.Rocquefelte at cnrs-imn.fr

  > To: wien at zeus.theochem.tuwien.ac.at

      > Subject: Re: [Wien] exchange coupling constants calculations

  > 

  > Dear Vincent,

  > 

  > Yes for sure. To estimate magnetic exchange coupling
  parameters you 

  > need to do a mapping based on total energies of different
  magnetic 

  > orders. WIEN2k allows to have total energies with high
  accuracy and 

  > using different functionals (depending of the system you are
  

  > considering). So yes, using WIEN2k to estimate J values is an
  

  > excellent choice.

  > 

  > Regards

  > 

  > Xavier

  > 

  > 

  > 

  > "Linux PC"  a ?crit :

  > 

  > >

  > >

  > > Dear Dr. Blaha and Wien2k users,

  > >

  > > Is it possible to use the Wien2k to calculate j magnetic
  exchange 

  > > coupling constants?

  > >

  > > Thank you very much,

  > > Vincent

  > >

  > 

  > 

  > ___

  > Wien mailing list

  > Wien at zeus.theochem.tuwien.ac.at

  > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

  
___
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien




  


___
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien 
  
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[Wien] exchange coupling constants calculations

[Guillaume Radtke]

Dear Vincent,

We also employed the method described by Xavier Rocquefelte based on the use of 
a large 
number of broken symmetry configurations + least-square fit to get magnetic 
couplings
up to the fourth nearest neighbors in a vanadate (CsV2O5). You can find the 
details
of the methodology in : Phys. Rev. Lett. 106 (2011) 177203. 

Regards,
Guillaume.



Le 17 mai 2011 ? 21:02, Linux PC a ?crit :

> Dear Dr. Blaha and Wien2k users,
> 
> Is it possible to use the Wien2k to calculate j magnetic exchange coupling 
> constants?
> 
> Thank you very much,
> Vincent
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

Dr Guillaume Radtke
IM2NP - UMR 6242 CNRS
Universit? Paul C?zanne Aix Marseille III
Tel : 04 91 28 90 12
Fax : 04 91 28 27 93
New Email : guillaume.radtke at im2np.fr



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[Wien] exchange coupling constants calculations

[Rocquefelte]

Dear Vincent,

The rule is quite simple. Let's take the example of a monoatomic linear 
chain.
To obtain the J parameter coupling two adjacent magnetic centers, you 
simply have to do 2 calculations:

- one with the ferromagnetic order: FM
- one with the antiferromagnetic order: AFM

You will then obtain two total energies, i.e. E(FM) and E(AFM).

Considering an Heisenberg Hamiltonian, you have:

E(FM) = N?/4 * (-J)

and

E(AFM) = N?/4 * (+J)

Then E(AFM) - E(FM) = N?/4 * (2*J) = N?/2 * J

where N is the number of unpaired electrons on the magnetic center.

For example, for N = 1:

J = 2 * (E(AFM) - E(FM))

The present example is very simple and you could imagine that for more 
complex structures it will be more difficult to realize a mapping 
analysis. Then the idea is:
- to use more magnetic orders than unknown J parameters
- to do a least-square procedure to find the J values ...

Here is and example of calculations I did with Peter and Karlheinz on CuO:

http://iopscience.iop.org/0953-8984/22/4/045502

If you do not have access to the paper, I could send it to you.

Regards

Xavier





Le 18/05/2011 12:31, Linux PC a ?crit :
> Dear Xavier,
>
> Thank you very much for the answer! I actually was looking through the 
> manual before, unfortunately, did not succeed in finding any 
> information on exchange interactions. Would you know, or may be other 
> users, if any practical manual exists for calculating of J.
>
> Thank you!
> Vincent
>
> > Date: Wed, 18 May 2011 07:24:52 +0200
> > From: Xavier.Rocquefelte at cnrs-imn.fr
> > To: wien at zeus.theochem.tuwien.ac.at
> > Subject: Re: [Wien] exchange coupling constants calculations
> >
> > Dear Vincent,
> >
> > Yes for sure. To estimate magnetic exchange coupling parameters you
> > need to do a mapping based on total energies of different magnetic
> > orders. WIEN2k allows to have total energies with high accuracy and
> > using different functionals (depending of the system you are
> > considering). So yes, using WIEN2k to estimate J values is an
> > excellent choice.
> >
> > Regards
> >
> > Xavier
> >
> >
> >
> > "Linux PC"  a ?crit :
> >
> > >
> > >
> > > Dear Dr. Blaha and Wien2k users,
> > >
> > > Is it possible to use the Wien2k to calculate j magnetic exchange
> > > coupling constants?
> > >
> > > Thank you very much,
> > > Vincent
> > >
> >
> >
> > ___
> > Wien mailing list
> > Wien at zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

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[Wien] exchange coupling constants calculations

[Linux PC]

Dear Xavier,

Thank you very much for the answer! I actually was looking through the manual 
before, unfortunately, did not succeed in finding any information on exchange 
interactions. Would you know, or may be other users, if any practical manual 
exists for calculating of J.

Thank you!
Vincent

> Date: Wed, 18 May 2011 07:24:52 +0200
> From: Xavier.Rocquefelte at cnrs-imn.fr
> To: wien at zeus.theochem.tuwien.ac.at
> Subject: Re: [Wien] exchange coupling constants calculations
> 
> Dear Vincent,
> 
> Yes for sure. To estimate magnetic exchange coupling parameters you  
> need to do a mapping based on total energies of different magnetic  
> orders. WIEN2k allows to have total energies with high accuracy and  
> using different functionals (depending of the system you are  
> considering). So yes, using WIEN2k to estimate J values is an  
> excellent choice.
> 
> Regards
> 
> Xavier
> 
> 
> 
> "Linux PC"  a ?crit :
> 
> >
> >
> > Dear Dr. Blaha and Wien2k users,
> >
> > Is it possible to use the Wien2k to calculate j magnetic exchange  
> > coupling constants?
> >
> > Thank you very much,
> > Vincent
> >
> 
> 
> ___
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
  
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[Wien] exchange coupling constants calculations

[xavier.rocquefe...@cnrs-imn.fr]

Dear Vincent,

Yes for sure. To estimate magnetic exchange coupling parameters you  
need to do a mapping based on total energies of different magnetic  
orders. WIEN2k allows to have total energies with high accuracy and  
using different functionals (depending of the system you are  
considering). So yes, using WIEN2k to estimate J values is an  
excellent choice.

Regards

Xavier



"Linux PC"  a ?crit?:

>
>
> Dear Dr. Blaha and Wien2k users,
>
> Is it possible to use the Wien2k to calculate j magnetic exchange  
> coupling constants?
>
> Thank you very much,
> Vincent
>

[Wien] exchange coupling constants calculations

[Linux PC]

Dear Dr. Blaha and Wien2k users,

Is it possible to use the Wien2k to calculate j magnetic exchange coupling 
constants?

Thank you very much,
Vincent
  
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