#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 11/30/2017 16:46:33
# Database entry: 1.1.36 NaFeSi2O6
# Cif-like file for the case 1.1.36


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                    'Na Fe Si2 O6'
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         .


_citation_journal_abbrev        "PHYSICAL REVIEW B"
_citation_journal_volume        91
_citation_page_first            ?
_citation_page_last             ?
_citation_article_id            214415
_citation_year                  2015
_citation_DOI                   10.1103/PhysRevB.91.214415

loop_
_citation_author_name
"M. Baum"
"A.C. Komarek"
"S. Holbein"
"M.T. Fernandez-Diaz"
"G. Andre"
"A. Hiess"
"Y. Sidis"
"P. Steffens"
"P. Becker"
"L. Bohaty"
"M. Braden"




_atomic_positions_source_database_code_ICSD  .
_atomic_positions_source_other               .

_transition_temperature     9
_experiment_temperature     6.1

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mLD2 2 1 . primary 4 .

_exptl_crystal_magnetic_properties_details
;
NPD
Another incommensurate phase with an helical arrangement appears below 6K (see entry #1.37)
The magnetic modulation of the Fe sites were modeled as transverse collinear, but the phase symmetry or the active irrep allows a more general arrangement.
Fourier components of the modulation for the symmetry independent Fe site are only given rough approximate values corresponding to the parameters reported in the original reference.
Amplitude of modulation: 3.0(3), angle with c axis: 8(6), phase shift between modulation of atoms related by inversion: 0.22 radians
;

_active_magnetic_irreps_details
;
1k magnetic incommensurate structure
MSSG associated to the action of single irrep mode.
The active irrep and the corresponding MSSG allows an arbitrary phase shift between the a and c components of the modulation, and therefore allows for a helical elliptical modulation.
Space inversion is conserved through the opposite chiralities of the modulations of the sites related by inversion.
The MSSG allows four free parameters for the 1k spin modulation. The collinear model reduces them to three.
;

_parent_space_group.name_H-M_alt              'C 2/c'
_parent_space_group.IT_number             15
_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 0.780000 0.000000


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

_space_group.magn_ssg_name  "C2/c1'(0\b0)s0s"
_space_group.magn_point_group_name  "2/m1'"
_space_group.magn_point_group_number  "5.2.13"
_cell_length_a                 9.6618(5)
_cell_length_b                 8.7933(4)
_cell_length_c                 5.2946(2)
_cell_angle_alpha              90
_cell_angle_beta               107.334(3)
_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,-x2,-x3,-x4,+1
4 x1,-x2,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+1/2,x2+1/2,x3,x4,+1
3 x1,x2,x3,x4+1/2,-1
4 x1+1/2,x2+1/2,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
Na1 Na 0 0.3002 0.25 1
Fe1 Fe 0 0.8994 0.25 1
Si1 Si 0.2905 0.0903 0.2379 1
O1 O 0.1137 0.0796 0.1384 1
O2 O 0.3595 0.2551 0.3041 1
O3 O 0.3526 0.0089 0.0105 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 0.5 -0.1 mxc1 mxs1
Fe1 y 1 0 0 0 0
Fe1 z 1 3 -0.6 mzc1 mzs1


