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Here are example files of a tetragonal antiferromagnet with nearest neighbour interactions, all files are equivalent:
# simple antiferromagnet #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) #! a=4.3843 b=4.3843 c=2.4194 alpha= 90 beta= 90 gamma= 90 #! r1a= 1 r2a= 0 r3a= 0 #! r1b= 0 r2b= 1 r3b= 0 primitive lattice vectors [a][b][c] #! r1c= 0 r2c= 0 r3c= 1 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=0 sipffilename=Ce3p.sipf # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] +0 +0 +1 -0.1 -0.1 -0.1 0 0 0 0 0 0 +0 +0 -1 -0.1 -0.1 -0.1 0 0 0 0 0 0 #
Using diagonalexchange this may be shortened to
# simple antiferromagnet #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) #! a=4.3843 b=4.3843 c=2.4194 alpha= 90 beta= 90 gamma= 90 #! r1a= 1 r2a= 0 r3a= 0 #! r1b= 0 r2b= 1 r3b= 0 primitive lattice vectors [a][b][c] #! r1c= 0 r2c= 0 r3c= 1 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=1 sipffilename=Ce3p.sipf # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] +0 +0 +1 -0.1 -0.1 -0.1 +0 +0 -1 -0.1 -0.1 -0.1 #
with indexexchange option the sequence of two ion interaction parameters can be changed and zero parameters may be omitted:
# simple antiferromagnet #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) #! a=4.3843 b=4.3843 c=2.4194 alpha= 90 beta= 90 gamma= 90 #! r1a= 1 r2a= 0 r3a= 0 #! r1b= 0 r2b= 1 r3b= 0 primitive lattice vectors [a][b][c] #! r1c= 0 r2c= 0 r3c= 1 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=2 sipffilename=Ce3p.sipf # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] #! indexexchange = JaJa JaJc JcJa JbJb JcJc +0 +0 +1 -0.1 0 0 -0.1 -0.1 +0 +0 -1 -0.1 0 0 -0.1 -0.1 #
# simple antiferromagnet #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) #! a=4.3843 b=4.3843 c=2.4194 alpha= 90 beta= 90 gamma= 90 #! r1a= 1 r2a= 0 r3a= 0 #! r1b= 0 r2b= 1 r3b= 0 primitive lattice vectors [a][b][c] #! r1c= 0 r2c= 0 r3c= 1 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=2 sipffilename=Ce3p.sipf # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] #! indexexchange = 1,1 1,3, 3,1 2,2 3,3 +0 +0 +1 -0.1 0 0 -0.1 -0.1 +0 +0 -1 -0.1 0 0 -0.1 -0.1 #
using symmetricexchange together with indexexchange will assume that the interaction tensor is symmetic and only half of it may be given:
# simple antiferromagnet #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) #! a=4.3843 b=4.3843 c=2.4194 alpha= 90 beta= 90 gamma= 90 #! r1a= 1 r2a= 0 r3a= 0 #! r1b= 0 r2b= 1 r3b= 0 primitive lattice vectors [a][b][c] #! r1c= 0 r2c= 0 r3c= 1 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=2 sipffilename=Ce3p.sipf # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] #! symmetricexchange=1 indexexchange = JaJa JaJc JbJb JcJc +0 +0 +1 -0.1 0 -0.1 -0.1 +0 +0 -1 -0.1 0 -0.1 -0.1 #
For magnetoelastic problems elastic constants and magnetoelastic interactions can be entered in the following form,
for the definition of the magnetoelastic constants
see equation (132):
# antiferromagnet with magnetoelastic interactions #<!--mcphase.mcphas.j--> #*************************************************************** # Lattice Constants (A) # Lattice Constants (A) #! a=8.062 b=8.062 c=8.062 alpha=90 beta=90 gamma=90 #! r1a=0 r2a=0.5 r3a=0.5 #! r1b=0.5 r2b=0 r3b=0.5 primitive lattice vectors [a][b][c] #! r1c=0.5 r2c=0.5 r3c=0 #! nofatoms=1 nofcomponents=3 number of atoms in primitive unit cell/number of components of each spin # #! Primitive Unit Cell Volume [A^3]: pVol=130.999123582 # Nonzero Elastic constants in meV per primitive unit cell in Voigt notation only first index<=second index has to be given # because the constants are symmetric Celij=Celji # Elastic constants refer to the Euclidean coordinate system ijk defined # with respect to abc as j||b, k||(a x b) and i normal to k and j # Note: these elastic constants refer to the elastic energy in the Hemiltonian # and do not necessarily correspond to the experimental elastic constants # a) if phonon degrees of freedom are present, use elastic constants as created by # makenn (see manual section on Crystal field Phonon Interaction - Elastic energy) # b) if only magnetic ions are present - use effective elastic constants # as measured at high temperature or computed by mcphasit or reduce_unitcell from a # phonon model #! Cel11=+121111.877 Cel12=+35479.1703 Cel13=+35479.1703 #! Cel22=+121111.877 Cel23=+35479.1703 #! Cel33=+121111.877 #! Cel44=+35479.1703 #! Cel55=+35479.1703 #! Cel66=+35479.1703 #! unit conversion: 1 meV/Primitive Unit Cell Volume =0.00122304635038043 GPa # # **************************************************************************** #! da= 0 [a] db= 0 [b] dc= 0 nofneighbours=2 diagonalexchange=2 sipffilename=Ce3p.sipf # G indices: # epsilon_alphabeta(strain tensor indices-Voigt Notation),gamma(I-operator index, see so1ion Module definition) # .... this is explicitely .... # eps6,O22S eps4,O21S eps1,O20 eps2,O20 eps3,O20 ... #! Gindices= 6,4 4,5 1,6 2,6 3,6 5,7 1,8 2,8 4,17 6,18 6,19 1,20 2,20 4,21 6,21 1,22 4,23 6,23 1,24 2,24 # corresponding magnetoelastic constants (meV) #! G= 21.28 42.56 10.64 10.64 -21.28 42.56 -31.9231.92 -0.462 -0.132 0.066 0.0642 0.064 0.096 0.066 -0.126 0.126 0.46 0.448 0.448 0.228 # da[a] db[b] dc[c] Jaa[meV] Jbb[meV] Jcc[meV] Jab[meV] Jba[meV] Jac[meV] Jca[meV] Jbc[meV] Jcb[meV] #! symmetricexchange=1 indexexchange = JaJa JaJc JbJb JcJc +0 +0 +1 -0.1 0 -0.1 -0.1 +0 +0 -1 -0.1 0 -0.1 -0.1 #