#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 11/30/2017 16:45:45
# Database entry: 1.1.17 Ba3NbFe3Si2O14
# Cif-like file for the case 1.1.17


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                    'Ba3 Nb Fe3 Si2 O1 4'
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         .


_citation_journal_abbrev        "PHYSICAL REVIEW LETTERS"
_citation_journal_volume        101
_citation_page_first            ?
_citation_page_last             ?
_citation_article_id            247201
_citation_year                  2008
_citation_DOI                   10.1103/PhysRevLett.101.247201

loop_
_citation_author_name
"K. Marty"
"V. Simonet"
"E. Ressouche"
"R. Ballou"
"P. Lejay"
"P. Bordet"




_atomic_positions_source_database_code_ICSD   162894
_atomic_positions_source_other               .

_transition_temperature     27
_experiment_temperature     2

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mDT1 2 1 . primary 3 .

_exptl_crystal_magnetic_properties_details
;
NSD and also spin polarized diffraction
circular approximation for the spin helix with Fe spin modulus of 4 Bohr magnetons.
Alternative model in PHYSICAL REVIEW B 88, 104417 (2013). Unfortunately the model in this reference could not be fully interpreted and transformed into an unambiguous description within the superspace formalism, in order to be included in this collection.
This alternative model has an additional modulation component along c, but it does not seem to correspond to a generalization of the model here, and its superspace symmetry would be different, the two models being therefore in contradiction.
Positional structure from room temperature.
Fe1 sine spin modulation components along the (1,2,0) direction given with non significant digits to produce the reported spin modulus of the helix.
;

_active_magnetic_irreps_details
;
Elliptical spin oblique helix along c with elliptical axes forced by the MSSG to be along (1,0,0) and a variable direction of type (x,2x,z). The model reported implies z=0, restricting the helix plane to the ab plane. The sign of the spin helicity is not forced by symmetry.
2-dim active irrep, which means a one to one correspondence with the MSSG, but less free parameters than in the representation approach, due to the inclusion of the symmetry properties for operations changing k into -k.
Helices of the other Fe atom in the basic unit cell are related by three fold rotation, which means that the 120¼ spin arrangement on the xy plane is forced by the MSSG.
So-called positive triangular chirality among the helices is also forced by the MSSG. The opposite triangular chirality corresponds to a different irrep and MSSG.
;

_parent_space_group.name_H-M_alt              'P 321'
_parent_space_group.IT_number             150
_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 0.000000 0.000000 0.143000


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

_space_group.magn_ssg_name  "P3211'(00\g)000s"
_space_group.magn_point_group_name  "321'"
_space_group.magn_point_group_number  "18.2.66"
_cell_length_a                 8.539(1)
_cell_length_b                 8.539(1)
_cell_length_c                 5.2414(1)
_cell_angle_alpha              90
_cell_angle_beta               90
_cell_angle_gamma              120

loop_
_space_group_symop_magn_ssg_operation.id
_space_group_symop_magn_ssg_operation.algebraic
1 x1,x2,x3,x4,+1
2 -x2,x1-x2,x3,x4,+1
3 -x1+x2,-x1,x3,x4,+1
4 x2,x1,-x3,-x4,+1
5 x1-x2,-x2,-x3,-x4,+1
6 -x1,-x1+x2,-x3,-x4,+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
Ba1 Ba 0.56598(2) 0 0 1
Nb1 Nb 0 0 0 1
Fe1 Fe 0.24964(4) 0 0.5 1
Si1 Si 0.666667 0.333333 0.5220(1) 1
O1 O 0.666667 0.333333 0.2162(4) 1
O2 O 0.5259(2) 0.7024(2) 0.3536(3) 1
O3 O 0.7840(2) 0.9002(2) 0.7760(3) 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
Fe1 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
Fe1 x 1 4 -2.31 mxc1 mxs1
Fe1 y 1 0 -4.62 0 2*mxs1
Fe1 z 1 0 0 0 mzs1


