Research/Sitter/MAGNDATA / 1.1.138_MnBi2Se4.mcif

MnBi₂Se₄

MAGNDATA entry 1.1.138 · 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 ≤ 15 K (−258 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	C21′(0,β,0)ss
Point group	21′
Parent space group	C 2/m No. 12
Repeats every	2.81 cells along b (not a whole number: that's what incommensurate means)
Propagation	[0 0.356 0] 1k
Cell	a 13.357 · b 4.073 · c 15.301 Å · α 90° · β 115.89° · γ 90°
Transition	15 K (−258 °C)
Measured at	4.2 K
Magnetic ions	Mn
Largest moment component	3.83 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′(0,β,0)ss →

Atom sites · 8 sites · CSV

site	element	x	z
Bi1	Bi	0.214	0.364
Bi2	Bi	0.353	0.138
Mn1	Mn	0	0.5
Mn2	Mn	0	0
Se1	Se	0.66	0.042
Se2	Se	0.011	0.172
Se3	Se	0.602	0.442
Se4	Se	0.82	0.314

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

J. K. Clark et al. Crystals (2021) · doi:10.3390/cryst11030242

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.138_MnBi2Se4.mcif from MAGNDATA · entry page

sha256 of this copy: d52a87997db77066da5e187dd559afef7613381b0d1ae8adb435f5151f759044
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.138_MnBi2Se4.mcif.