Reference: A. Morozkin, O. Isnard, P. Henry, S. Granovsky, R. Nirmala and P. Manfrinetti, Journal of Alloys and Compounds (2006) 420 34-36. DOI: 10.1016/j.jallcom.2005.10.051 Atomic positions from: ICSD #154766
Parent space group (paramagnetic phase): P-3m1 (#164) Propagation vector: k1 (0, 0, 0)
Transition Temperature: 120 K Experiment Temperature: 4 K
Lattice parameters of the magnetic unit cell:
4.51920 4.51920 7.39980 90.00 90.00 120.00 Transformation from parent structure: (a,b,c;0,0,0)
[View matrix form]
Transformation matrix from the setting of the parent structure (ap,bp,cp) to the working setting (a,b,c):
2-dim irrep as primary. Although this irrep alone for a general direction can result in the observed MSG, the reported direction of the moments on the basal plane is along a special direction which keeps a higher monoclinic C2'/m symmetry. Not clear how in this case the direction on the xy plane, which usually remains undetermined when analyzing powder data could in this case be fully determined. The reduction to triclinic P-1' is due to the z-component of the Mn moments, which corresponds the 1-dim irrep mGM1-, which must then be taken as a second primary irrep.
The zero moment at the Yb site is symmetry-forced.