#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 11/19/2017 16:55:37
# Database entry: 0.103 Mn2GeO4
# Cif-like file for the case 0.103


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                    'Mn2 Ge O4'
_chemical_formula_weight                 ?
_chemical_melting_point                  ?
_chemical_compound_source                ?
_chemical_absolute_configuration         .


_citation_journal_abbrev        "PHYSICAL REVIEW LETTERS"
_citation_journal_volume        108
_citation_page_first            ?
_citation_page_last             ?
_citation_article_id            077204
_citation_year                  2012
_citation_DOI                   10.1103/PhysRevLett.108.077204

loop_
_citation_author_name
"J.S. White"
"T. Honda"
"K. Kimura"
"T. Kimura"
"C. Niedermayer"
"O. Zaharko"
"A. Poole"
"B. Roessli"
"M. Kenzelmann"






_atomic_positions_source_database_code_ICSD  .
_atomic_positions_source_other               .

_transition_temperature     5.5
_experiment_temperature     1.4

loop_
_irrep_id
_irrep_dimension
_irrep_small_dimension
_irrep_direction_type
_irrep_action
_irrep_modes_number
_irrep_presence
mGM1+ 1 1 . primary ? ?
mGM2+ 1 1 . primary ? ?

_exptl_crystal_magnetic_properties_details
;
NSD
between 17K-47K and 17K-5.5K other commensurate magnetic phases (see entries #0.101 and #0.102)
An incommensurate modulation is also reported for this phase. The model here corresponds to only the k=0 component of the magnetic ordering.
The incommensurate modulation breaks further the point-group symmetry into a polar one, and the phase is reported to be multiferroic, with a magnetically induced ferroelectricity along c.
;

_active_magnetic_irreps_details
;
1k magnetic structure
Two 1-dim irreps active. Equivalence between the MSG and the two irreps assignment.
This k=0 ordering breaks the magnetic point group symmetry to 2/m (monoclinic axis along c). The incommensurate modulation breaks it further to magnetic point group 2.
FM along c
;

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

loop_
_parent_propagation_vector.id
_parent_propagation_vector.kxkykz
k1 [0 0 0]

_parent_space_group.child_transform_Pp_abc  'a,b,c;0,0,0'
_space_group_magn.transform_BNS_Pp_abc  '-b,-c,a;0,0,0'


_space_group_magn.number_BNS  14.75
_space_group_magn.name_BNS  "P  2_1/c"
_space_group_magn.point_group_name  "2/m"
_space_group_magn.point_group_number  "5.1.12"
_cell_length_a                 10.6926(1)
_cell_length_b                 6.2851(1)
_cell_length_c                 5.0557(1)
_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+1/2,-y,z+1/2,+1
3 -x,-y,-z,+1
4 x+1/2,y,-z+1/2,+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
Mn1_1 Mn 0.00000 0.00000 0.00000 1
Mn1_2 Mn 0.00000 0.50000 0.00000 1
Mn2 Mn 0.2794(2) 0.25000 0.9903(5) 1
Ge1 Ge 0.0968(1) 0.25000 0.04346(2) 1
O1 O 0.0934(2) 0.25000 0.7782(3) 1
O2 O 0.4466(1) 0.25000 0.2202(3) 1
O3_1 O 0.1650(1) 0.0298(2) 0.2754(2) 1
O3_2 O 0.8350 0.5298 0.7246 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
Mn1_1 1.9 2.8 0.3 mx,my,mz
Mn1_2 1.7 2.4 -0.3 mx,my,mz
Mn2 2.9 3.4 0.0 mx,my,mz

