#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 03/10/2021 

data_5yOhtAoR
_audit_creation_date            2021-03-10
_audit_creation_method          "Bilbao Crystallographic Server"

_citation_journal_abbrev        "JOURNAL OF APPLIED PHYSICS"
_citation_journal_volume        40
_citation_page_first            1124
_citation_page_last             1125
_citation_article_id            .
_citation_year                  1969
_citation_DOI                   10.1063/1.1657557

loop_
_citation_author_name
"D. E. Cox"
"B. C. Frazer"
"R. E. Newnham"
"R. P. Santoro"

_atomic_positions_source_database_code_ICSD  164258
_atomic_positions_source_other               .

_transition_temperature     28
_experiment_temperature     4.2

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mDT2 2 1 general primary 6 .
mDT4 2 1 special primary 6 .

_exptl_crystal_magnetic_properties_details
;
NPD
Position structure from a determination at 150K
Non-standard Pbnm parent setting
Polar along a (setting Pbnm). Possible magnetically induced ferroelectricity (type II multiferroic).
The wavelength of the cycloidal modulation in the graphical representation of the paper is inconsistent with the value given in the text. The value in the text has been assumed correct.
;

_active_magnetic_irreps_details
;
1k incommensurate magnetic structure
The MSSG is used here with an origin shift along x4 with respect to what could be a standard choice, which minimize the translations along x4 of the symmetry operations
Two irreps as primary. Their modulations superposed in quadrature.
Not clear if all possible degrees of freedom allowed by the magnetic symmetry of the model were checked. 
;

_parent_space_group.name_H-M_alt  'P b n m'
_parent_space_group.IT_number             62
_parent_space_group.transform_Pp_abc  'a,b,c;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 0.00000 0.00000 0.087


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

_space_group.magn_ssg_name  "P2_1nm1'(0,0,g)0s0s"
_space_group.magn_point_group_name  "mm21'"
_space_group.magn_point_group_number  7.2.21
_cell_length_a                 4.55500
_cell_length_b                 9.79200
_cell_length_c                 5.66300
_cell_angle_alpha              90.00000
_cell_angle_beta               90.00000
_cell_angle_gamma              90.00000

loop_
_space_group_symop_magn_ssg_operation.id
_space_group_symop_magn_ssg_operation.algebraic
1 x1,x2,x3,x4,+1
2 x1+1/2,-x2+1/2,-x3,-x4+1/2,+1
3 x1,x2,-x3+1/2,-x4,+1
4 x1+1/2,-x2+1/2,x3+1/2,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
Cr1_1 Cr 0.00000 0.00000 0.00000 1
Cr2_1 Cr 0.49500 0.23200 0.75000 1
Cr2_2 Cr 0.00500 0.73200 0.75000 1
Be1_1 Be -0.06900 0.40600 0.75000 1
Be1_2 Be 0.56900 -0.09400 0.75000 1
O1_1 O 0.27700 0.40700 0.75000 1
O1_2 O 0.22300 -0.09300 0.75000 1
O2_1 O 0.73100 0.06100 0.75000 1
O2_2 O 0.76900 0.56100 0.75000 1
O3_1 O 0.25700 0.16200 0.02200 1
O3_2 O 0.24300 0.66200 0.47800 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 0.00000 0.00000 0.00000 0,0,0
Cr2_1 0.00000 0.00000 0.00000 0,0,0
Cr2_2 0.00000 0.00000 0.00000 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_1 x 1 1.55 0.00000 Mxc1 Mxs1
Cr1_1 y 1 0.00000 0.00000 Myc1 Mys1
Cr1_1 z 1 0.00000 -1.55 Mzc1 Mzs1
Cr2_1 x 1 0.00000 -2.75 0 Mxs1
Cr2_1 y 1 0.00000 0.00000 0 Mys1
Cr2_1 z 1 -2.75 0.00000 Mzc1 0
Cr2_2 x 1 0.00000 2.75 0 Mxs1
Cr2_2 y 1 0.00000 0.00000 0 Mys1
Cr2_2 z 1 2.75 0.00000 Mzc1 0

