Research/Sitter/MAGNDATA / 1.1.15_CaCr2O4.mcif

CaCr₂O₄

MAGNDATA entry 1.1.15 · 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 ≤ 21 K (−252 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	Pbnm1′(00γ)s00s
Point group	mmm1′
Parent space group	P b n m No. 62
Repeats every	2.1 cells along c (not a whole number: that's what incommensurate means)
Propagation	[0 0 0.477] 1k
Cell	a 10.639 · b 9.094 · c 2.96 Å · α 90° · β 90° · γ 90°
Transition	21 K (−252 °C)
Measured at	1.5 K
Magnetic ions	Cr
Largest moment component	2.88 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 Pbnm1′(00γ)s00s →

Atom sites · 7 sites · CSV

site	element	x	y	z
Ca1	Ca	0.6594	0.7593	0.25
Cr1	Cr	0.6124	0.4403	0.25
Cr2	Cr	0.101	0.4169	0.25
O1	O	0.1596	0.2007	0.25
O2	O	0.4757	0.1151	0.25
O3	O	0.786	0.5285	0.25
O4	O	0.4262	0.4177	0.25

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

F. Damay et al. PHYSICAL REVIEW B (2010) · doi:10.1103/PhysRevB.81.214405

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.15_CaCr2O4.mcif from MAGNDATA · entry page

sha256 of this copy: e36924609e508bb67141bdb611459fe912c053b819f4230940c279bbde33d2ce
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.15_CaCr2O4.mcif.