#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 11/19/2017 17:20:27
# Database entry: 3.4 MgCr2O4
# Cif-like file for the case 3.4


data_5yOhtAoR
_audit_creation_date            2017-11-19
_audit_creation_method          "Bilbao Crystallographic Server"

_chemical_name_systematic
;
;
_chemical_name_common                    ?
_chemical_formula_moiety                 ?
_chemical_formula_structural             ?
_chemical_formula_analytical             ?
_chemical_formula_iupac                  ?
_chemical_formula_sum                    'Mg Cr2 O4'
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         .


_citation_journal_abbrev        "Phys. Rev. B"
_citation_journal_volume        1
_citation_page_first            3116
_citation_page_last             3124
_citation_article_id            .
_citation_year                  1970
_citation_DOI                   10.1103/PhysRevB.1.3116

loop_
_citation_author_name
"H. Shaked"
"J.M. Hastings"
"L.M. Corliss"




_atomic_positions_source_database_code_ICSD  .
_atomic_positions_source_other               .

_transition_temperature     16
_experiment_temperature     14

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mX2 6 2 special-2 primary 2 .
mX4 6 2 special-2 primary 2 .
mX3 6 2 special-2 secondary 1 no
mGM4+ 3 3 special secondary 2 no

_exptl_crystal_magnetic_properties_details
;
NPD and NSD
The orientation of the basal component on the moment on the plane ab is undetermined, and has been chosen along a direction that maximizes the symmetry.
Modulus of the magnetic moment forced equal on the three sites: 0.7
cubic setting with origin choice 1
Later (J. Phys.: Condens. Matter 20 (2008) 104238), a structural phase transition has been reported  to happen simultaneously with the magnetic ordering, with a different propagation vector, which refutes this model.
;

_active_magnetic_irreps_details
;
3k magnetic structure
The model includes correlations among the spins of the three independent sites that are not symmetry forced.
Superposition of two irreps acting as primary (mX2 with k=(0,0,1) and mX4 for k=(0,1,0) and (1,0,0). The model also correlates the amplitudes of the two irreps.
Not clear if more simple models associated with a single active irrep for the three k-vectors have been tried.
;

_parent_space_group.name_H-M_alt  'F  d  -3m'
_parent_space_group.IT_number                       227
_parent_space_group.transform_Pp_abc  'a,b,c;0,0,0'

loop_
_parent_propagation_vector.id
_parent_propagation_vector.kxkykz
k1 [0 0 1]
k2 [0 1 0]
k3 [1 0 0]

_parent_space_group.child_transform_Pp_abc  'a,b,c;-1/8,-1/8,-1/8'
_space_group_magn.transform_BNS_Pp_abc  'a,b,c;1/2,1/2,1/2'


_space_group_magn.number_BNS  111.255
_space_group_magn.name_BNS  "P  -42'm'  "
_space_group_magn.point_group_name  "-42'm'"
_space_group_magn.point_group_number  "14.5.52"
_cell_length_a                 8.33500
_cell_length_b                 8.33500
_cell_length_c                 8.33500
_cell_angle_alpha              90.00
_cell_angle_beta               90.00
_cell_angle_gamma              90.00

loop_
_space_group_symop_magn_operation.id
_space_group_symop_magn_operation.xyz
1 x,y,z,+1
2 -x,-y,z,+1
3 y,-x,-z,+1
4 -y,x,-z,+1
5 x,-y,-z,-1
6 -x,y,-z,-1
7 -y,-x,z,-1
8 y,x,z,-1

loop_
_space_group_symop_magn_centering.id
_space_group_symop_magn_centering.xyz
1 x,y,z,+1

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Mg1_1 Mg 0.25000 0.25000 0.25000 1
Mg1_2 Mg 0.00000 0.50000 0.50000 1
Mg1_3 Mg 0.00000 0.00000 0.00000 1
Mg1_4 Mg 0.50000 0.50000 0.00000 1
Cr1_1 Cr 0.12500 0.12500 0.12500 1
Cr1_2 Cr 0.87500 0.37500 0.62500 1
Cr1_3 Cr 0.37500 0.62500 0.87500 1
O1_1 O 0.38900 0.38900 0.38900 1
O1_2 O 0.61100 0.11100 0.88900 1
O1_3 O 0.11100 0.88900 0.61100 1
O1_4 O 0.13900 0.63900 0.36100 1
O1_5 O 0.86100 0.86100 0.86100 1
O1_6 O 0.63900 0.36100 0.13900 1

loop_
_atom_site_moment.label
_atom_site_moment.crystalaxis_x
_atom_site_moment.crystalaxis_y
_atom_site_moment.crystalaxis_z
_atom_site_moment.symmform
Cr1_1 0.4 0.4 0.4 mx,mx,mz
Cr1_2 -0.4 0.4 -0.4 mx,my,mz
Cr1_3 -0.4 0.4 0.4 mx,-mx,mz

