Research/Sitter/MAGNDATA / 0.402_Sr4Fe4O11.mcif

Sr₄Fe₄O₁₁

MAGNDATA entry 0.402 · source

d-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. d-wave: the splitting changes sign twice around the Fermi surface (2 nodal planes).

Spin group ²m²m¹m: each symmetry marked ¹ keeps every spin, ² swaps up and down.

ordered ≤ 232 K (−41 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 10 properties

Magnetic group	C m m′ m′ BNS 65.486
Parent space group	C m m m No. 65
Spins	collinear · 2 nodal planes · net moment 0 μ_B per cell
Propagation	[0 0 0] 1k
Cell	a 10.943 · b 7.6795 · c 5.4549 Å · α 90° · β 90° · γ 90°
Transition	232 K (−41 °C)
Measured at	1.5 K
Magnetic ions	Fe
Largest moment component	3.52 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 m m′ m′ →

Atom sites · 8 sites · CSV

site	element	x	y	z	m_a	m_b	m_c	\|m\| (μ_B)
Sr1	Sr	0.5	0	0.5
Sr2	Sr	0	0	0.5
Sr3	Sr	0.26	0	0
Fe1	Fe	0	0.741	0
Fe2	Fe	0.25	0.25	0.5	0	3.52	0	3.52
O1	O	0.5	0	0
O2	O	0.268	0	0.5
O3	O	0.381	0.2726	0.241

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 Schmidt et al. J. Phys.: Condens. Matter (2003) · doi:10.1088/0953-8984/15/50/0032003

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 0.402_Sr4Fe4O11.mcif from MAGNDATA · entry page

sha256 of this copy: f62c68677469009b9e8b10e598e130bcfef9ab63838bb5378d7220ca7e847d4a
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 0.402_Sr4Fe4O11.mcif.