INPUT_isolated_sk_DMI_D2d_y.mif

# MIF 2.1 ---------------------------------------------------------------------

# Generate an isolated skyrmion with interfacial (C_nv) DMI
#
# Authors: D. Cortes, M. Beg, H.Fangohr (2018)

set PI [expr {4 * atan(1.)}]
set MU0 [expr {4 * $PI * 1e-7}]

# -----------------------------------------------------------------------------
# PdFe on Ir(111) [PRL, 114(17):1-5, 2015]
# This is an interfacial system but the parameters should work similarly for 
# the D2d symmetry. Spins only change the sense of rotation
set Ms [expr {1.1e6}]
set A  [expr {2e-12}]
set D  [expr {3.9e-3}]
set KU [expr {2.5e6}]
set BZ [expr {1.0}]

set XL [expr {15e-9}]
set YL [expr {2e-9}]
set ZL [expr {$XL}]

set xcell [expr {$XL / 20}]
set ycell [expr {2e-9}]
set zcell [expr {$ZL / 20}]

# -----------------------------------------------------------------------------

# BoxAtlas
Specify Oxs_BoxAtlas:atlas [subst {
  xrange {0 $XL}
  yrange {0 $YL}
  zrange {0 $ZL}
  name atlas
}]

# RectangularMesh
Specify Oxs_RectangularMesh:mesh [subst {
  cellsize {$xcell $ycell $zcell}
  atlas Oxs_BoxAtlas:atlas
}]

# UniformExchange
Specify Oxs_UniformExchange [subst {
  A $A
}]

# Uniaxial Anisotropy
Specify Oxs_UniaxialAnisotropy:Anisotropy [subst {
	axis { 0 0 1 }
	K1 $KU
}]

# D_2d DMI
Specify Oxs_DMI_D2d_y [subst {
  default_D $D
  atlas :atlas
  D {
    atlas atlas $D
  }
}]

Specify Oxs_FixedZeeman:Bfield [subst {
  comment {Field values in Tesla; scale to A/m}
  multiplier [expr {1 / $MU0}]
  field {0.0 0.0 $BZ}
}]

# CGEvolver
Specify Oxs_CGEvolve {}

# MinDriver
Specify Oxs_MinDriver [subst {
  evolver Oxs_CGEvolve
  stopping_mxHxm 0.01
  mesh :mesh
  Ms $Ms
  m0 { Oxs_ScriptVectorField {
     atlas :atlas
     script { dot }
     norm 1.0
     script_args { relpt }
  }}
 
  basename isolated_sk_D2d_y
  scalar_field_output_format {text %\#.15g}
  vector_field_output_format {text %\#.15g}
}]

Destination table mmArchive
Destination mags mmArchive

Schedule DataTable table Stage 1
Schedule Oxs_MinDriver::Magnetization mags Stage 1

# =============================================================================

proc dot { x y z } {
	set xnorm  [expr {(2 * $x - 1)}]
	set znorm  [expr {(2 * $z - 1)}]
    set radius [expr {sqrt($xnorm * $xnorm + $znorm * $znorm)}]
    if {$radius < 0.2} { return [list 0 -1 0] }
    return [list 0 1 0]
}