Anantharaman, M R; Shaijumon, M M; Narayanan, T N; Ajayan, P M(Springer, October 28, 2008)
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Abstract:
Magnetic nanowires (NWs) are ideal materials for the fabrication of various multifunctional nanostructures
which can be manipulated by an external magnetic fi eld. Highly crystalline and textured nanowires of nickel
(Ni NWs) and cobalt (Co NWs) with high aspect ratio (~330) and high coercivity have been synthesized
by electrodeposition using nickel sulphate hexahydrate (NiSO4·6H2O) and cobalt sulphate heptahydrate
(CoSO4·7H2O) respectively on nanoporous alumina membranes. They exhibit a preferential growth along〈110〉.
A general mobility assisted growth mechanism for the formation of Ni and Co NWs is proposed. The role of
the hydration layer on the resulting one-dimensional geometry in the case of potentiostatic electrodeposition
is verified. A very high interwire interaction resulting from magnetostatic dipolar interactions between the
nanowires is observed. An unusual low-temperature magnetisation switching for fi eld parallel to the wire axis
is evident from the peculiar high fi eld M(T) curve
Anantharaman, M R; Shaijumon, M M; Ajayan, P M; Narayanan, T N(Springer, October 21, 2009)
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Abstract:
Hybrid magnetic nanostructures with high
coercivity have immense application potential in various
fields. Nickel (Ni) electrodeposited inside Cobalt (Co)
nanotubes (a new system named Ni @ Co nanorods) were
fabricated using a two-step potentiostatic electrodeposition
method. Ni @ Co nanorods were crystalline, and they have
an average diameter of 150 nm and length of *15 lm.
The X-ray diffraction studies revealed the existence of two
separate phases corresponding to Ni and Co. Ni @ Co
nanorods exhibited a very high longitudinal coercivity. The
general mobility-assisted growth mechanism proposed for
the growth of one-dimensional nanostructures inside nano
porous alumina during potentiostatic electrodeposition is
found to be valid in this case too