Research/Sitter/MAGNDATA / 1.1.25_LiFeAs2O7.mcif

LiFeAs₂O₇

MAGNDATA entry 1.1.25 · 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 ≤ 35 K (−238 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	C11′(αβγ)0s
Point group	11′
Parent space group	C 2 No. 5
Repeats every	1.41 cells along a (not a whole number: that's what incommensurate means)
Propagation	[0.709 0 0.155] 1k
Cell	a 6.6786 · b 8.2855 · c 4.7429 Å · α 90° · β 103.95° · γ 90°
Transition	35 K (−238 °C)
Measured at	2 K
Magnetic ions	Fe
Largest moment component	4.343 μ_B
Method	NPD

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 C11′(αβγ)0s →

Atom sites · 11 sites · CSV

site	element	x	y	z
Li1	Li	0	0.617	0
Fe1	Fe	0	0	0
As1_1	As	0.7824	0.337	0.591
As1_2	As	0.2176	0.337	0.409
O1_1	O	0.7497	0.4811	0.8237
O1_2	O	0.2503	0.4811	0.1763
O2_1	O	0.831	0.1567	0.7473
O2_2	O	0.169	0.1567	0.2527
O3_1	O	0.61	0.317	0.2773
O3_2	O	0.39	0.317	0.7227
O4	O	0	0.4147	0.5

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

G. Rousse et al. PHYSICAL REVIEW B (2013) · doi:10.1103/PhysRevB.88.214433

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.25_LiFeAs2O7.mcif from MAGNDATA · entry page

sha256 of this copy: 7996a01860a60aafbccd34c600e7e529da3db66656c789b388c4c0037aa8f0e7
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.25_LiFeAs2O7.mcif.