Research/Sitter/MAGNDATA / 0.722_Mn4Nb2O9.mcif

Mn₄Nb₂O₉

MAGNDATA entry 0.722 · source

altermagnet

No net magnetisation, yet the electron bands are spin-split: the up and down spin sublattices are related only by a rotation or mirror, never by a shift or inversion.

Spin group ²2/²m: each symmetry marked ¹ keeps every spin, ² swaps up and down.

ordered ≤ 52.1 K (−221 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	C c BNS 9.37
Point group	m
Parent space group	C c No. 9
Spins	collinear · 1 nodal planes · net moment 0 μ_B per cell
Propagation	[0 0 0] 1k
Cell	a 9.9054 · b 5.3097 · c 13.2052 Å · α 90° · β 92.77° · γ 90°
Transition	52.1 K (−221 °C)
Measured at	35 K
Magnetic ions	Mn
Largest moment component	2.68 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 C c →

Atom sites · 15 sites · CSV

site	element	x	y	z	m_a	m_b	m_c	\|m\| (μ_B)
Mn1	Mn	0.735	0.535	0.42	0	0	−2.68	2.68
Mn2	Mn	0.448	0.476	0.463	0	0	2.68	2.68
Mn3	Mn	0.394	0.5	0.757	0	0	−2.68	2.68
Mn4	Mn	0.558	0	0.592	0	0	2.68	2.68
Nb1	Nb	0.109	0.508	0.82
Nb2	Nb	0.776	0.492	0.647
O1	O	0.73	0.698	0.787
O2	O	0.193	0.687	0.701
O3	O	0.126	0.87	0.071
O4	O	0.863	0.334	0.538
O5	O	0.523	0.663	0.359
O6	O	0.571	0.191	0.452
O7	O	0.791	0.844	0.397
O8	O	0.464	0.893	0.733
O9	O	0.4	0.291	0.619

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

E. Solana-Madruga et al. Chem. Commun. (2021) · doi:10.1039/d1cc02782d

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 0.722_Mn4Nb2O9.mcif from MAGNDATA · entry page

sha256 of this copy: 5ef5fb424d230c2960ca816d1cb168855bdb0d11bfcaafa1c8950cf3403d27e5
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 0.722_Mn4Nb2O9.mcif.