Research/Sitter/MAGNDATA / 0.229_Ba2MnSi2O7.mcif

Ba₂MnSi₂O₇

MAGNDATA entry 0.229 · source

g-wave 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. g-wave: 4 nodal planes.

Spin group ¹4/¹m²m²m: each symmetry marked ¹ keeps every spin, ² swaps up and down.

ordered ≤ 3 K (−270 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 10 properties

Magnetic group	P 4 2₁ m BNS 113.267
Parent space group	P 4 2₁ m No. 113
Spins	collinear · 4 nodal planes · net moment 0 μ_B per cell
Propagation	[0 0 0] 1k
Cell	a 8.3205 · b 8.3205 · c 5.371 Å · α 90° · β 90° · γ 90°
Transition	2.95 K (−270 °C)
Measured at	1.6 K
Magnetic ions	Mn
Largest moment component	4.1 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 P 4 2₁ m →

Atom sites · 6 sites · CSV

site	element	x	y	z	m_a	m_b	m_c	\|m\| (μ_B)
Ba1	Ba	0.1649	0.6649	0.5086
Mn1	Mn	0	0	0	0	0	4.1	4.1
Si1	Si	0.6342	0.1342	0.9486
O1	O	0	0.5	0.1441
O2	O	0.0775	0.199	0.1872
O3	O	0.6383	0.1383	0.2508

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

M. Sale et al. Inorganic Chemistry (2019) · doi:10.1021/acs.inorgchem.8b03195

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 0.229_Ba2MnSi2O7.mcif from MAGNDATA · entry page

sha256 of this copy: 38816862bd450c9473b4fb079ea057434e9cced72e4b3da4b4bd925b2a00fc74
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 0.229_Ba2MnSi2O7.mcif.