86 lines
2.0 KiB
ReStructuredText
86 lines
2.0 KiB
ReStructuredText
.. index:: compute spin
|
|
|
|
compute spin command
|
|
====================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
compute ID group-ID spin
|
|
|
|
* ID, group-ID are documented in :doc:`compute <compute>` command
|
|
* spin = style name of this compute command
|
|
|
|
Examples
|
|
""""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
compute out_mag all spin
|
|
|
|
Description
|
|
"""""""""""
|
|
|
|
Define a computation that calculates magnetic quantities for a system
|
|
of atoms having spins.
|
|
|
|
This compute calculates the following 6 magnetic quantities:
|
|
|
|
* the three first quantities are the x,y and z coordinates of the total
|
|
magnetization,
|
|
* the fourth quantity is the norm of the total magnetization,
|
|
* The fifth quantity is the magnetic energy (in eV),
|
|
* The sixth one is referred to as the spin temperature, according
|
|
to the work of :ref:`(Nurdin) <Nurdin1>`.
|
|
|
|
The simplest way to output the results of the compute spin calculation
|
|
is to define some of the quantities as variables, and to use the thermo and
|
|
thermo_style commands, for example:
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
compute out_mag all spin
|
|
|
|
variable mag_z equal c_out_mag[3]
|
|
variable mag_norm equal c_out_mag[4]
|
|
variable temp_mag equal c_out_mag[6]
|
|
|
|
thermo 10
|
|
thermo_style custom step v_mag_z v_mag_norm v_temp_mag
|
|
|
|
This series of commands evaluates the total magnetization along z, the norm of
|
|
the total magnetization, and the magnetic temperature. Three variables are
|
|
assigned to those quantities. The thermo and thermo_style commands print them
|
|
every 10 timesteps.
|
|
|
|
Output info
|
|
"""""""""""
|
|
|
|
The array values are "intensive". The array values will be in
|
|
metal units (:doc:`units <units>`).
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
|
|
The *spin* compute is part of the SPIN package. This compute is only
|
|
enabled if LAMMPS was built with this package. See the :doc:`Build package <Build_package>` doc page for more info. The atom_style
|
|
has to be "spin" for this compute to be valid.
|
|
|
|
**Related commands:**
|
|
|
|
none
|
|
|
|
Default
|
|
"""""""
|
|
|
|
|
|
none
|
|
|
|
----------
|
|
|
|
.. _Nurdin1:
|
|
|
|
**(Nurdin)** Nurdin and Schotte Phys Rev E, 61(4), 3579 (2000)
|