#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 11/30/2017 16:45:41
# Database entry: 1.1.15 CaCr2O4
# Cif-like file for the case 1.1.15


data_5yOhtAoR
_audit_creation_date            2017-11-30
_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                    'Ca Cr2 O4'
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         .


_citation_journal_abbrev        "PHYSICAL REVIEW B"
_citation_journal_volume        81
_citation_page_first            ?
_citation_page_last             ?
_citation_article_id            214405
_citation_year                  2010
_citation_DOI                   10.1103/PhysRevB.81.214405

loop_
_citation_author_name
"F. Damay"
"C. Martin"
"V. Hardy"
"A. Maignan"
"G. Andre"
"K. Knight"
"S.R. Giblin"
"L.C. Chapon"




_atomic_positions_source_database_code_ICSD   8288
_atomic_positions_source_other               .

_transition_temperature     21
_experiment_temperature     1.5

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mDT3 2 1 . primary 6 .

_exptl_crystal_magnetic_properties_details
;
NPD
The four Cr atoms of each Cr orbit have cycloidal modulations on the plane ac with opposite chiralities by pairs. This relation is forced by the MSSG. Non polar global symmetry.
Spin cycloids are symmetry protected.
The system has been incorrectly attributed a polar point group. The actual point group of the reported structure is the centrosymmetric mmm1'.
Non-standard parent setting Pbnm
Nuclear structure taken from icsd_8288 and not from reference.
;

_active_magnetic_irreps_details
;
1k magnetic structure
k-maximal magnetic symmetry.
One to one correspondence between the MSSG and the active irrep.
A discarded alternative sinusoidal model has lower symmetry.
Symmetry allows an oblique tilt of the plane of spin rotations around the c axis.
Not clear if the experiment could distinguish the absolute chirality of the cycloidal modulations of the symmetry independent sites.
;

_parent_space_group.name_H-M_alt              'P b n m'
_parent_space_group.IT_number             62
_parent_space_group.transform_Pp_abc    'b,c,a;0,0,0'

_cell_modulation_dimension               1

loop_
_cell_wave_vector_seq_id
_cell_wave_vector_x
_cell_wave_vector_y
_cell_wave_vector_z
1 0.000000 0.000000 0.477000


_parent_space_group.child_transform_Pp_abc  'a,b,c;0,0,0'

_space_group.magn_ssg_name  "Pbnm1'(00\g)s00s"
_space_group.magn_point_group_name  "mmm1'"
_space_group.magn_point_group_number  "8.2.25"
_cell_length_a                 10.639
_cell_length_b                 9.094
_cell_length_c                 2.96
_cell_angle_alpha              90
_cell_angle_beta               90
_cell_angle_gamma              90

loop_
_space_group_symop_magn_ssg_operation.id
_space_group_symop_magn_ssg_operation.algebraic
1 x1,x2,x3,x4,+1
2 -x1,-x2,x3+1/2,x4+1/2,+1
3 -x1+1/2,x2+1/2,-x3+1/2,-x4,+1
4 x1+1/2,-x2+1/2,-x3,-x4+1/2,+1
5 -x1,-x2,-x3,-x4,+1
6 x1,x2,-x3+1/2,-x4+1/2,+1
7 x1+1/2,-x2+1/2,x3+1/2,x4,+1
8 -x1+1/2,x2+1/2,x3,x4+1/2,+1

loop_
_space_group_symop_magn_ssg_centering.id
_space_group_symop_magn_ssg_centering.algebraic
1 x1,x2,x3,x4,+1
2 x1,x2,x3,x4+1/2,-1

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Ca1 Ca 0.6594 0.7593 0.25 1
Cr1 Cr 0.6124 0.4403 0.25 1
Cr2 Cr 0.101 0.4169 0.25 1
O1 O 0.1596 0.2007 0.25 1
O2 O 0.4757 0.1151 0.25 1
O3 O 0.786 0.5285 0.25 1
O4 O 0.4262 0.4177 0.25 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 0 0 0 0,0,0
Cr2 0 0 0 0,0,0

loop_
_atom_site_Fourier_wave_vector.seq_id
_atom_site_Fourier_wave_vector.q1_coeff
1 1

loop_
_atom_site_moment_Fourier.atom_site_label
_atom_site_moment_Fourier.axis
_atom_site_moment_Fourier.wave_vector_seq_id
_atom_site_moment_Fourier_param.cos
_atom_site_moment_Fourier_param.sin
_atom_site_moment_Fourier_param.cos_symmform
_atom_site_moment_Fourier_param.sin_symmform
Cr1 x 1 2.88 0 mxc1 0
Cr1 y 1 0 0 myc1 0
Cr1 z 1 0 1.27 0 mzs1
Cr2 x 1 -2.88 0 mxc1 0
Cr2 y 1 0 0 myc1 0
Cr2 z 1 0 1.27 0 mzs1


