Research/Sitter/MAGNDATA / 1.1.37_NaFeSi2O6.mcif

NaFeSi₂O₆

MAGNDATA entry 1.1.37 · source

incommensurate spiral

Incommensurate: the magnetic pattern repeats every so many cells, but not a whole number of them, so it never lines up with the crystal lattice. Here it's a spiral: the spin direction rotates as you move along.

ordered ≤ 6 K (−267 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	C21′(0β0)ss
Point group	21′
Parent space group	C 2/c No. 15
Repeats every	1.28 cells along b (not a whole number: that's what incommensurate means)
Propagation	[0 0.78 0] 1k
Cell	a 9.6618 · b 8.7933 · c 5.2946 Å · α 90° · β 107.334° · γ 90°
Transition	6 K (−267 °C)
Measured at	1.9 K
Magnetic ions	Fe
Largest moment component	3.3 μ_B
Method	NSD

Symmetry

Stereogram of the magnetic point group: each operation applied to one direction. Filled = upper hemisphere, ring = lower; red operations include time reversal. Lines are mirrors; polygons are 2/3/4/6-fold axes; the centre ring is inversion.

Every structure in C21′(0β0)ss →

Atom sites · 12 sites · CSV

site	element	x	y	z
Na1_1	Na	0	0.3002	0.25
Na1_2	Na	0	−0.3002	−0.25
Fe1_1	Fe	0	0.8994	0.25
Fe1_2	Fe	0	−0.8994	−0.25
Si1_1	Si	0.2905	0.0903	0.2379
Si1_2	Si	−0.2905	−0.0903	−0.2379
O1_1	O	0.1137	0.0796	0.1384
O1_2	O	−0.1137	−0.0796	−0.1384
O2_1	O	0.3595	0.2551	0.3041
O2_2	O	−0.3595	−0.2551	−0.3041
O3_1	O	0.3526	0.0089	0.0105
O3_2	O	−0.3526	−0.0089	−0.0105

Incommensurate: the moments are modulated; the picture evaluates each atom's Fourier series at its own phase.

Moment components are along the crystal axes a, b, c (μ_B), as magCIF writes them. Symmetry generates the rest of the cell from these sites.

Source

Baum, M et al. PHYSICAL REVIEW B (2015) · doi:10.1103/PhysRevB.91.214415

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.37_NaFeSi2O6.mcif from MAGNDATA · entry page

sha256 of this copy: 5e3f2dc5972d5a8f62bb35dd71abb9bbcae23a7201113f6928d38e4023ee1510
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.37_NaFeSi2O6.mcif.