Tabby graphene: Dimensional magnetic crossover in fluorinated graphite

• Published in: Scientific reports Vol. 7; no. 1; pp. 16544 - 8
• Main Authors: Makarova, T. L., Shelankov, A. L., Shames, A. I., Zyrianova, A. A., Komlev, A. A., Chekhova, G. N., Pinakov, D. V., Bulusheva, L. G., Okotrub, A. V., Lähderanta, E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-11-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/357; 639/925/918; Domestic animals; Fluorine; Graphite; High temperature; Humanities and Social Sciences; Hybridization; Interfaces; Magnetic susceptibility; Magnetism; multidisciplinary; Science; Science (multidisciplinary); Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-16321-5

Tabby
is a pattern of short irregular stripes, usually related to domestic cats. We have produced
Tabby
patterns on graphene by attaching fluorine atoms running as monoatomic chains in crystallographic directions. Separated by non-fluorinated
sp
2
carbon ribbons,
sp
3
-hybridized carbon atoms bonded to zigzag fluorine chains produce
sp
2
-
sp
3
interfaces and spin-polarized edge states localized on both sides of the chains. We have compared two kinds of fluorinated graphite samples C
2
F
x
, with
x
near to 1 and
x
substantially below 1. The magnetic susceptibility of C
2
F
x
(
x
 < 1) shows a broad maximum and a thermally activated spin gap behaviour that can be understood in a two-leg spin ladder model with ferromagnetic legs and antiferromagnetic rungs; the spin gap constitutes about 450 K. Besides, stable room-temperature ferromagnetism is observed in C
2
F
x
(
x
 < 1) samples: the crossover to a three-dimensional magnetic behaviour is due to the onset of interlayer interactions. Similarly prepared C
2
F
x
(
x
 ≈ 1) samples demonstrate features of two-dimensional magnetism without signs of high-temperature magnetic ordering, but with transition to a superparamagnetic state below 40 K instead. The magnetism of the
Tabby
graphene is stable until 520 K, which is the temperature of the structural reconstruction of fluorinated graphite.