17.1 MIF 1.1

17.1.7 Miscellaneous

  • Converge |mxh| Value: Nominal value to use as a stopping criterion: When 𝐦×𝐡 (i.e., 𝐌×𝐇/Ms2) at all spins in the simulation is smaller than this value, it is assumed that a relaxed (equilibrium) state has been reached for the current applied field. This is a dimensionless value.
    NOTE: This Record Identifier is deprecated. Use Default Control Point Spec instead.

  • Randomizer Seed: Value with which to seed random number generator. Optional. Default value is 0, which uses the system clock to generate a semi-random seed.

  • Max Time Step: Limit the maximum ODE step size to no larger than this amount, in seconds. Optional.

  • Min Time Step: Limit the minimum ODE step size to no less than this amount, in seconds. Optional.

  • User Comment: Free-form comment string that may be used for problem identification. Optional.

 

Figure 17.1: Example MIF 1.1 file. (description)
# MIF 1.1
#
# Example from the OOMMF User’s Guide.
#
# All units are SI.
#
################# MATERIAL PARAMETERS ######################
Ms:  800e3                # Saturation magnetization in A/m.
A:   13e-12               # Exchange stiffness in J/m.
K1:  0.5e3                # Anisotropy constant in J/m^3.
Anisotropy Type: uniaxial # One of <uniaxial|cubic>.
Anisotropy Dir1: 1 0 0    # Directional cosines wrt to
                          # coordinate axes

################# DEMAG SPECIFICATION ######################
Demag Type: ConstMag # One of <ConstMag|3dSlab|2dSlab
                     #         |3dCharge|FastPipe|None>.

#################### PART GEOMETRY #########################
Part Width:     0.25e-6    # Nominal part width in m
Part Height:    1.0e-6     # Nominal part height in m
Part Thickness: 1e-9       # Part thickness in m.
Cell Size:      7.8125e-9  # Cell size in m.
#Part Shape:    # One of <Rectangle|Ellipse|Oval|Mask>.
                # Optional.

################ INITIAL MAGNETIZATION #####################
Init Mag: Uniform 90 45 # Initial magnetization routine
                        # and parameters

################ EXPERIMENT PARAMETERS #####################
# Field Range:  Start_field  Stop_field  Steps
Field Range: -.05 -.01 0.  .05  .01 0. 100
Field Range:  .05  .01 0. -.05 -.01 0. 100
Field Type: Multi 4 \
 7 Ribbon 1 0 1.0e-6 0.25e-6 1.0e-6 1e-9 \
 7 Ribbon 1 0 0      0.25e-6 0      1e-9 \
 9 Tie 100 0 0 0.12e-6 0.5e-6 0.13e-6 0.5e-6 8e-9 \
 1 Uniform
# The above positions ribbons of positive charge along the
# upper and lower edges with strength Ms, applies a large
# (100 Ms) field to the center cells, and also applies a
# uniform field across the sample stepped from
# (-.05,-.01,0.) to (.05,.01,0.) (Tesla), and back, in
# approximately 0.001 T steps.

Default Control Point Spec: -torque 1e-6
# Assume equilibrium has been reached, and step the applied
# field, when the reduced torque |mxh| drops below 1e-6.

################ OUTPUT SPECIFICATIONS #####################
Base Output Filename: samplerun
Magnetization Output Format: binary 8 # Save magnetization
# states in binary format with full (8-byte) precision.

#################### MISCELLANEOUS #########################
Randomizer Seed: 1   # Random number generator seed.
User Comment: Example MIF 1.1 file, with lots of comments.