# [Pw_forum] magnetic moment

Guido Fratesi fratesi at mater.unimib.it
Thu Oct 11 17:08:27 CEST 2012

On 10/11/2012 04:10 PM, Sakhrawi Taoufek wrote:
> i read that the value of starting magnetization is used to brake the
> up/dw symmetry  in the charge density but when i fix all parameters and
> i change the values of starting magnetization the value of total
> magnetization and
> the magnetic moment of each atom changes. U can't understand the
> relation between starting magnetization, total magnetization and the
> local magnetic moment
> thinx

Starting magnetization is about the initial guess of the SCF cycle.

Total/local magnetization is about the converged (or willing to
converge) spin-dependent charge density.

May the difference in the two concepts be not clear to someone, some

If the system is "easy", the final result should not depend on the
initial guess. That is not always the case, unfortunately, as magnetic
structures often display several E[\rho] minima so you might need to
play a bit with the starting guess to cover all possibilities and find
the global minimum.

Guido

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Guido Fratesi

Dipartimento di Scienza dei Materiali
Universita degli Studi di Milano-Bicocca
via Cozzi 53, 20125 Milano, Italy

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