Sections:
All simulation parameters can be set in the configuration file allopt.txt . The default configuration file allopt.txt in the $MAGPAR_HOME/src/doc/ subdirectory is thoroughly documented. Any option defined in this file can be overridden by an environment variable or command line option (cf. PETSc manual chapter 14 - Other PETSc Features). This useful feature is used in example mumag3: mumag standard problem #3 .
Additional PETSc internal logging/info/diagnostic options, which may slow down the simulations (!), are given in allopt_log.txt .
Deprecated and removed options can be found in Sec. allopt_ret.txt .
For each grain (or part of the model with distinct property id) this file contains a line defining its material properties.
The grain with property id 1 is assigned the properties in line 1, the grain with property id 2 is assigned the properties in line 2, etc.
psi defines the third Euler angle for cubic anisotropy
example.krn:
0.0 0.0 5.00E+06 0.0 1.32 1.40E-11 0.1 uni # property 1 0.0 0.0 1.50E+07 0.0 1.32 1.40E-11 0.1 uni # property 2 # # theta phi K1 K2 Js A alpha psi # parameter # (rad) (rad) (J/m^3) (J/m^3) (T) (J/m) (1) (rad) # units # theta and phi: direction of the uniaxial magnetocrystalline anisotropy axis in spherical coordinates (rad); # theta measured from the z-axis, phi measured from the x-axis in the x-y-plane # K1: first magnetocrystalline anisotropy constant (J/m3) # set <0 for in-plane anisotropy # K2: second magnetocrystalline anisotropy constant (J/m3) # Js: saturation polarization (Tesla) # set to -1 to have volumes with the given property id removed # A: exchange constant (J/m) # alpha: Gilbert damping constant (dimensionless); set to 999 to "lock" magnetization # psi: third Euler angle for cubic anisotropy (see http://mathworld.wolfram.com/EulerAngles.html) # or use "uni" for uniaxial anisotropy # additional material parameters # just examples, no warranty for accuracy! # # theta phi K1 K2 Js A alpha psi # parameter # (rad) (rad) (J/m^3) (J/m^3) (T) (J/m) (1) (rad) # units # 0.0 0.0 4.60E+04 1.5e4 2.15 2.50E-11 0.1 0.0 # Kneller, Ferromagnetismus. Berlin, Springer, 1962 (cubic anisotropy!) # E. F. Kneller, R. Hawig, IEEE Trans. Magn. 27 (1991) 3588-3560 # L. W. McKeehan, Phys. Rev. 51, 136-139 (1937) 0.0 0.0 4.00E+04 0.0 0.40 1.32E-11 0.1 uni # gamma-Fe2O3 (Maghemite): Johansson, J.M.M.M. 173 (1997) 5-14 (value of exchange constant unknown!) 0.0 0.0 4.50E+05 0.0 1.76 1.30E-11 0.1 uni # Co: Yang, J. Appl. Phys. 87 (2000) 6884 0.0 0.0 4.60E+06 0.0 1.60 9.86E-12 0.1 uni # Nd2Fe14B: Klemmer, Script. Met. 33 no. 10/11 (1995) 1793-1805 # Weller, IEEE Trans. Magn. 36 (2000) 10-15 0.0 0.0 0.0 0.0 1.00 1.05E-11 0.1 uni # Permalloy: N. Smith, D. Markham, and D. LaTourette, J. Appl. Phys. 65, 4362 (1989) 0.0 0.0 5.00E+06 0.0 1.32 1.40E-11 0.1 uni # Sm2Co17: Durst, Phys. Stat. Sol. (a) 108 (1988) 403 0.0 0.0 9.00E+06 0.0 0.80 1.40E-11 0.1 uni # SmCo5: Durst, Phys. Stat. Sol. (a) 108 (1988) 403 0.0 0.0 1.50E+07 0.0 1.32 1.40E-11 0.1 uni # SmCo5: Tang, IEEE Trans. Magn. 37 (2001) 2515 0.0 0.0 1.80E+06 0.0 1.38 1.03E-11 0.1 uni # FePd (L1_0): Klemmer, Script. Met. 33 no. 10/11 (1995) 1793-1805 uni # Weller, IEEE Trans. Magn. 36 (2000) 10-15 0.0 0.0 6.60E+06 0.0 1.43 1.02E-11 0.1 uni # FePt (L1_0): Klemmer, Script. Met. 33 no. 10/11 (1995) 1793-1805 uni # Weller, IEEE Trans. Magn. 36 (2000) 10-15 1.5707963 0 3.9788736e4 0.0 1.00 1.00E-11 0.1 uni # mumag standard problem #3 http://www.ctcms.nist.gov/~rdm/mumag.html
For each grain (or part of the model with distinct property id) this file contains a line defining its magnetoelastic properties.
example.kst
7 17.5e-6 103.7e-6 -1e9 0.0 0.0 # Fe65Co35: Bai, J. Appl. Phys. 95 (2004) 6864-6866. # # texture lambda100 lambda111 sigmaX sigmaY sigmaZ # parameter # (-) (erg/cm^3)(erg/cm^3)(Pa) (Pa) (Pa) # units # # texture # ======= # id theta phi psi comment # ------------------------------------------------------------------------- # 0: disable stress effects # 1: 0 0 0 # 2: 0 random random 100 texture, the film normal z is [001] direction # 3: pi/2 0 3pi/4 # 4: pi/2 random 3pi/4 110 texture, the film normal z is [110] direction # 5: pi/2 pi asin(sqrt(2/3))) # 6: asin(sqrt(2/3))) random 3pi/4 111 texture, the film normal z is [111] direction # 7: random random random random texture # # lambda100: magnetoelastic constant in 100 direction # lambda111: magnetoelastic constant in 111 direction # sigmaX: stress in x direction (unit Pa) # sigmaY: stress in y direction (unit Pa) # sigmaZ: stress in z direction (unit Pa)
The finite element mesh can be imported in two formats:
A short tutorial can be found in section Preprocessing .
(optional)
magpar stores the magnetization distribution, magnetostatic potential, and local fields in UCD files. These UCD files, which contain the finite element mesh, can be used to read the finite element mesh as well as the magnetization distribution. This allows you to modify some parameters (e.g. the external field) and restart simulations from any magnetization distribution. The Cartesian components of the magnetization (Mx,My,Mz) are read from the second, third and fourth column of the vertex data section of the inp file. The first column contains the vertex id.
A short tutorial on postprocessing and visualization of magpar's output can be found in section Postprocessing.