Research/Sitter/MAGNDATA / 0.23_Ca3Mn2O7.mcif

Ca₃Mn₂O₇

MAGNDATA entry 0.23 · 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 ≤ 110 K (−163 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	C m′ c 2₁′ BNS 36.174
Point group	m′m2′
Parent space group	C m c 2₁ No. 36
Spins	collinear · 2 nodal planes · net moment 0 μ_B per cell
Propagation	[0 0 0] 1k
Cell	a 19.4462 · b 5.2453 · c 5.2399 Å · α 90° · β 90° · γ 90°
Transition	110 K (−163 °C)
Measured at	10 K
Magnetic ions	Mn
Largest moment component	2.67 μ_B
Method	NPD, SXD

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′ c 2₁′ →

Atom sites · 7 sites · CSV

site	element	x	y	z	m_a	m_b	m_c	\|m\| (μ_B)
Ca1	Ca	0.5	0.752	0.744
Ca2	Ca	0.3135	0.753	0.775
Mn1	Mn	0.0974	0.753	0.75	2.67	0	0	2.67
O1	O	0	0.7	0.756
O2	O	0.0882	0.0391	−0.039
O3	O	0.1044	0.5338	0.027
O4	O	0.1952	0.7807	0.747

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.V. Lobanov et al. J. Phys. Cond. Matter (2004) · doi:10.1088/0953-8984/16/29/023

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 0.23_Ca3Mn2O7.mcif from MAGNDATA · entry page

sha256 of this copy: 473c08d790b789cf56d5617827a3ef6b666798b8d4691d7afb854b0eb5836de4
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 0.23_Ca3Mn2O7.mcif.