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