AW: [Wien] I want to calculate FeNi with lower symmetry(MAE is too sensitive to the input parameter)

[Pavel Novak]

Dear colleague,

to calculate MAE is difficult. It can help, if you use the 'force theorem'
as the results are there less sensitive to the input parameters.
Description of how to do it with the WIEN may be found in our paper
PRB 66, 184434 (2002), which also contains reference to the original paper
of Methefessel and Kubler.

Pavel Novak

_________________________________________________
Dr. Pavel Novak
Department of Magnetism and Superconductivity
Institute of Physics AS CR
Cukrovarnicka 10, 162 53 Praha 6, Czech Republic
tel: +420 2 20 318 532
e-mail: novakp at fzu.cz

On Wed, 30 Nov 2005 yasuharu_shiraishi at fujifilm.co.jp wrote:

>
> Dear P Blaha,
>
> Thank you for your advice!
> I understand reason of this problem!
>
> Sorry, I have more one question.
>
> I also calculated MAE of FePt ternary alloy using WIEN2k,
> and I used 10000 of k point that  I think it is large enough.
> But if I changed parameters, MAE value changed large.
>
> I calculated MAE of FePt as follows.
>
> I set coordinate of FePt as follows.
> (a=b=2.72236, c=3.71, Fe(0.0, 0.0, 0.0) Pt(0.5, 0.5, 0.5))
>
> I set calculation parameter as follows.
> k=10000
> Gmax=14.0
> Emax=10.0
> Rkmax=9.0
> MT radius(Rmt) of Fe = 2.50
> MT radius(Rmt) of Pt = 2.50
> P1/2 correction is added to both Fe and Pt.
> Easy axis is (0. 0. 1.) and hard axis is (1. 1. 0.)
>
> If I change Rmt of Fe from 2.50 to 2.52 and Rmt of Pt from 2.50 to 2.52 and
> I did not
> change other parameter, and MAE changes from 0.155mRy to
> 0.218mRy(RKmax=9.0)
>
> Further, Rkmax changes from 9.0 to 10.0 with Rmt=2.52(Fe and Pt same
> value),
> MAE value reversed from [001] to [110](!!)(MAE= -0.425Ry)
>
> I think MAE is too sensitive to the input parameter Rmt or Rkamx although
> parameter changes a little.
> So I have difficulty for determing MAE.
> Does MAE depend on a little bit parameter changing(Rmt only 0.02 bohr or
> Rkmax only 9.0 to 10.0)?
>
> Bset regards.
> Yasuharu shiraishi
>
>
>
>
>
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