Research/Sitter/MAGNDATA / 1.1.113_CeMn2Ge2.mcif

CeMn₂Ge₂

MAGNDATA entry 1.1.113 · 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 ≤ 320 K (47 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	I42′2′(0,0,γ)q00
Point group	42′2′
Parent space group	I 4/m m m No. 139
Repeats every	3.15 cells along c (not a whole number: that's what incommensurate means)
Propagation	[0 0 0.317] 1k
Cell	a 4.1301 · b 4.1301 · c 10.915 Å · α 90° · β 90° · γ 90°
Transition	320 K (47 °C)
Measured at	2 K
Magnetic ions	Ce, Mn
Largest moment component	2.25 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 I42′2′(0,0,γ)q00 →

Atom sites · 3 sites · CSV

site	element	y	z	m_a	m_b	m_c	\|m\| (μ_B)
Ce1	Ce	0	0
Mn1	Mn	0.5	0.25	0	0	1.52	1.52
Ge1	Ge	0	0.383

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

R. Welter et al. Journal of Alloys and Compounds (1995) · doi:10.1016/0925-8388(94)01378-0

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.113_CeMn2Ge2.mcif from MAGNDATA · entry page

sha256 of this copy: ff95470674dfa34e8b8854951ac1d6d6b7915723e83e7c38e3d18cbcd7e81cad
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.113_CeMn2Ge2.mcif.