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I n t e r n a t i o n a l C o n f e r e n c e o n
Metal, Mining and
Magnetic Materials
Journal of Material Sciences
ISSN: 2321-6212
N o v e m b e r 0 1 - 0 2 , 2 0 1 8
P a r i s , F r a n c e
Metal and Magnetism 2018
Page 34
G
reatactivityinspintronics-relatedfieldsinrecentfewyearsrevealedimportance
in combining magnetic metal nanoparticles and organic semiconductor that
promises new nanomaterials with attractive magnetic and electronic properties.
Here, we demonstrate the remarkable nanocomposites, formed through self-
assembling in the cobalt-fullerene mixture, which exhibit tunable magnetism. The
CoxC60 films (x<120) were fabricated by simultaneous deposition of Co and C60
onto the same substrate under controlled conditions. We found that magnetic
properties of the films strongly depends on the Co concentration x. The Co
x
C
60
films with x<2 demonstrate a ferromagnetic behaviour. At higher x (x>2), the films
become superparamagnetic. Such a magnetic transformation correlates with the
changes in the film nanostructure. In the interval of x<2, the film nanostructure
consists of the bulk fcc-C
60
and Co
2
C
60
phases only. At higher x (x>2), the Co
clustering occurs, and the film is a nanocomposite (NC) as the arrays of small
Co clusters (few nm in size) distributed in the C
60
-based matrix. Parameters
of the NC (size and fraction of the Co clusters) designate the features of the
superparamagnetic effect (coercive field, saturation magnetization, blocking
temperature
T
b
). Remarkable changes in the film magnetism occur upon the air
exposure of the CoxC
60
films. In particular, magnetization of such films revealed
vertical shift of the hysteresis loops suggesting the effect of interface exchange
magnetism. In the interval of x>30, the oxygen content in such films is dropped
down as well as Tb is increasing that reflects coalescence of the Co clusters. The
CoxC60 films with x>40 show ferromagnetic behaviour at room temperature that
allowed us to detect their magnetic domains using magnetic force microscopy.
The discovered magnetism of the Co
x
C
60
films designates their potential for
application in high-dense magnetic memory, sensors and catalysis
Biography
VasilyLavrentievhascompletedhisPhD in1984fromLeningrad
Polytechnic Institute (St. Petersburg, Russia). He received
Postdoctoral experience in Institute of Applied Physics (Sumy)
and Institute of Physics at Augsburg University (Augsburg). His
activity in nanoscience has been started from 2000 in Japan
Atomic Energy Research Institute (Takasaki). Presently, he is a
Researcher of Nuclear Physics Institute CAS. He has published
more than 140 papers in reputed journals.
lavrent@ujf.cas.czVariable magnetism of cobalt-fullerene
mixed system
Vasily Lavrentiev
1
, Alexandr Stupakov
2
and
Michail Motylenko
3
1
Nuclear Physics Institute-CAS, Czech Republic
2
Institute of Physics-CAS, Czech Republic
3
Institute of Material Science-Technische Universiatat Bergakademie
Freiberg, Germany
Vasily Lavrentiev et al., J Mat. Sci. 2018, Volume:6
DOI: 10.4172/2321-6212-C7-031