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orbital-moment

sam
2007-11-05
2013-06-05
  • sam

    sam - 2007-11-05

    Dear Exciting users,

    I am doing MCA (Magnetocrystalline energy) calculations using the force theorem, using the Fleur code i found some doubtful results about anisotropy in GdN.
    given that the exciting code is a FLAPW based code in which the SOC is added second-variation-ally (as in fleur) i would like to check these anisotropy calculations using exciting and also to discover more the exciting code.
    i have installed the exciting code, and i did a test for iron, i did a calculation for iron including soc, but i don't get the orbital moment values!!.
    I would like to know whether the orbital moment calculation is implemented in the exciting code or not??, and how to specify the different directions for the magnetization (to calculate  the MCA)?

    Thank you for all.
    Best regards.
    Sam

     
    • francesco cricchio

      Hello Sam,
      in order to specify the different directions for the magnetization you can change the global field or the local field on the atom as follows

      ! global field
      bfieldc
      0.01 0.01 0.01

      for example if you would like your magnetization along the (1,1,1) direction or on the single atom,

      atoms
        1                                   : nspecies
        'Fe.in'                             : spfname
        2                                   : natoms
        0.0  0.0  0.0    0.01  0.01  0.01     : atposl, bfcmt
        0.5  0.5  0.5   -0.01 -0.01 -0.01

      to get antiferromagnet along (1,1,1) direction.

      Note that it could be useful to perform few iteration with a large magnetic field to speed up the convergence.
      For example

      ! max number of iterations
      maxscl
      5

      atoms
        1                                   : nspecies
        'Fe.in'                             : spfname
        2                                   : natoms
        0.0  0.0  0.0    1.0  1.0   1.0     : atposl, bfcmt
        0.5  0.5  0.5   -1.0 -1.0  -1.0   

      and then reduce it and converge your calculation starting from the previous STATE.OUT containing magnetization and density. It is just necessary to change the flag task

      task
      1

      For what concern the orbital moment, you are right, it is not calculated explicitely and written out in the main output INFO.OUT.
      I just checked the code and all the "ingredients" to calculate it are already there, since SOC is implemented, so it should be quite fast to implement it. I will try to do it tomorrow and send the routine to Kay in order to be added for the next release.

      Hope this will help!

      Best

      Francesco

       
    • francesco cricchio

      Hello,
      we just realised that orbital moments components <Lx> <Ly> <Lz> are printed out by the code by using task=15.
      Best
      Francesco

       

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