MAGNDATA Collection of Magnetic Structures

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NiCr2O4 (#0.893) view in Jmol Download mcif file Download vesta file (all atoms) Download vesta file (magnetic atoms only)

Magnetic structure with all atoms

Magnetic structure with only magnetic atoms

• NPD
• In this phase, below 24K, two propagation vectors, k=0 and k=(0,0,1) (in Fddd setting), are observed. It is not clear if they correspond to two coexisting phases or to a single phase. Here, for simplicity, we describe the two corresponding magnetic arrangements separately. Here the one corresponding to the k=0 Ferrimagnetic arrangement is given, which is also present above 24K, up to 74K (see #0.892).
• For the spin arrangement proposed for k=(0,0,1), see #1.685. If indeed the two magnetic propagation vectors are present in a single phase, these two arrangements should be considered superposed on the same system.
• The structure has a very small structural distortion which lowers the efective space group from I4_1/amd to Fddd. As this structural distortion is simultaneous with the first magnetic ordering and consistent with the resulting MSG, it can be considered an induced effect, and we keep here the tetragonal space group as the parent symmetry.
• The magnetic structure is described in the paper within the Fddd setting, and this description is mantained here.
• The direction of the collinear moments on the plane xy, perpendiculat to the parent tetragonal axis, is undetermined. It is assumed to be along x (Fddd setting), for consistency with the weak induced Fddd structural distortion.
• Ferrimagnetic along x (Fddd setting) or direction (1,-1,0) in the parent tetragonal setting
• The FI direction is on the tetragonal basal plane, while in CuCr2O4, which is also reported in the same paper, although it is also along the x direction of the Fddd setting used, this direction in this second case corresponds to the parent tetragonal axis (see #0.891).

• 1k magnetic structure
• k-maximal magnetic symmetry
• 2-dim irrep along a special direction