#\#CIF_2.0
# Created by the Bilbao Crystallographic Server
# http://www.cryst.ehu.es
# Date: 10/10/2019

data_5yOhtAoR
_audit_creation_date            2019-10-10
_audit_creation_method          "Bilbao Crystallographic Server"

_citation_journal_abbrev        "Journal of Magnetism and Magnetic Materials"
_citation_journal_volume        231
_citation_page_first            162
_citation_page_last             171
_citation_article_id            ?
_citation_year                  2001
_citation_DOI                   10.1016/S0304-8853(01)00062-2

loop_
_citation_author_name
"P. Schobinger-Papamantellos"
"G. Andre"
"J. Rodriguez-Carvajal"
"O. Moze"
"W. Kockelmann"
"L. Tung"
"K. Buschow"




_atomic_positions_source_database_code_ICSD  .
_atomic_positions_source_other               .

_transition_temperature     17
_experiment_temperature     1.5

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

_exptl_crystal_magnetic_properties_details
;
NPD
The two Pr atoms related by inversion within the unit cell are modelled as having in phase spin modulations, instead of having modulations related by inversion. This breaks the inversion symmetry of the structure.
As the two atoms have different z coordinates, the parameterization in terms of q.r_i from the superspace formalism, which is used here, requires some specific k-dependent phase shift between the two modulations yielding non-zero amplitudes for both the sine and cosine modulation functions. Amplitudes given with non-significant digit to comply with the reported spin modulation amplitude: 2.24
;

_active_magnetic_irreps_details
;
1k incommensurate magnetic structure
The proposed spin modulation breaks the centrosymmetry of the structure and yields a polar structure.
It requires the incoherent superposition of two magnetic order parameters for the same irrep.
It seems that the proposed model was chosen ad-ho, and other more symmetric models, with a single order parameter and keeping the point group of the paramagnetic phase, were not explored.
As the MSSG of the structure does not include any operation transforming k into -k, one of the phases of the two independent Pr spin modulations can be fixed arbitrarily (here the sine function has been set to zero), and therefore the spin modulations has only 3 free parameters. The assumption that the two independent spin modulations are in phase reduces these three free parameters to one.
The longitudinal character of the spin modulation is symmetry protected
;

_parent_space_group.name_H-M_alt  'P m m a'
_parent_space_group.IT_number             51
_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 0.437000


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

_space_group.magn_ssg_name  "Pmm21'(00g)ss0s"
_space_group.magn_point_group_name  "mm21'"
_space_group.magn_point_group_number  7.2.21
_cell_length_a                 7.644
_cell_length_b                 4.0431
_cell_length_c                 6.8717
_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+1/2,-x2,x3,x4,+1
3 x1,-x2,x3,x4+1/2,+1
4 -x1+1/2,x2,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
Pr1_1 Pr 0.25 0 0.386 1
Pr1_2 Pr 0.75 0 0.614 1
Co1_1 Co 0.25 0 0.807 1
Co1_2 Co -0.25 0 -0.807 1
Al1 Al 0 0 0 1
Al2_1 Al 0.25 0.5 0.037 1
Al2_2 Al -0.25 -0.5 -0.037 1
Al3_1 Al 0.069 0.5 0.696 1
Al3_2 Al -0.069 -0.5 -0.696 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
Pr1_1 0 0 0 0,0,0
Pr1_2 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
Pr1_1 x 1 0 0 0 0
Pr1_1 y 1 0 0 0 0
Pr1_1 z 1 2.24 0 mzc1 mzs1
Pr1_2 x 1 0 0 0 0
Pr1_2 y 1 0 0 0 0
Pr1_2 z 1 1.815 1.31 mzc1 mzs1



