Commit2 JT 052019

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)

:link(ld,Manual.html)

:link(lc,Commands_all.html)

:line

pair_style spin/long command :h3

[Syntax:]

pair_style spin/long cutoff (cutoff)

cutoff = global cutoff pair (distance in metal units) :ulb,l

:ule

[Examples:]

pair_style spin/long 10.0

pair_coeff * * long 10.0

pair_coeff 2 3 long 8.0 :pre

[Description:]

Style {pair/spin/long} computes interactions between pairs of particles

that each have a magnetic spin.  

:c,image(Eqs/pair_spin_long_range.jpg)

where si and sj are two magnetic spins of two particles with Lande factors 

gi and gj respectively, eij = (ri - rj)/|ri-rj| is the unit vector between 

sites i and j, mu0 the vacuum permeability, muB the Bohr magneton (muB = 

5.788 eV/T in metal units). 

Style {pair/spin/long} computes magnetic precession vectors:

:c,image(Eqs/pair_spin_long_range_magforce.jpg)

with h the Planck constant (in metal units), and a mechanical force:

:c,image(Eqs/pair_spin_long_range_force.jpg)

The following coefficient must be defined for each pair of atoms

types via the "pair_coeff"_pair_coeff.html command as in the examples

above, or in the data file or restart files read by the

"read_data"_read_data.html or "read_restart"_read_restart.html

commands, or by mixing as described below:

rc (distance units) :ul

with rc is the radius cutoff of the short-range component of the 

long-range interaction (see "(Cerda)"_#Cerda1 for more

explanation).  

:line

[Restrictions:]

The {pair/spin/long} style is part of the SPIN package. It is only 

enabled if LAMMPS was built with that package. See the 

"Making LAMMPS"_Section_start.html#start_3 section for more info.

The {pair/spin/long} style computes the short-range component of

the dipole-dipole interaction. The functions evaluating the 

long-range component are part of the KSPACE package.

They can be enabled only if LAMMPS was built with that package.

[Related commands:]

"atom_style spin"_atom_style.html, "pair_coeff"_pair_coeff.html, 

[Default:] none

:line

:link(Tranchida6)

[(Tranchida)] Tranchida, Plimpton, Thibaudeau and Thompson,

Journal of Computational Physics, (2018).

:link(Cerda1)

[(Cerda)] Cerda, Ballenegger, Lenz, and Holm, J Chem Phys, 129(23), 

234104 (2008).

velocity 	all create 100 4928459 rot yes dist gaussian

pair_style 	hybrid/overlay eam/alloy spin/exchange 3.5

#pair_coeff 	* * eam/alloy Fe_Mishin2006.eam.alloy Fe

pair_coeff 	* * eam/alloy ../examples/SPIN/iron/Fe_Mishin2006.eam.alloy Fe

pair_coeff 	* * eam/alloy Fe_Mishin2006.eam.alloy Fe

pair_coeff 	* * spin/exchange exchange 3.4 0.02726 0.2171 1.841

neighbor 	0.1 bin

compute 	outsp all property/atom spx spy spz sp fmx fmy fmz

dump 		100 all custom 1 dump_iron.lammpstrj type x y z c_outsp[1] c_outsp[2] c_outsp[3]

run 		50

run 		50000