Heterogeneous Co20Cu80 alloy nanowires were prepared by electrodeposition a
nd their magnetic properties studied using SQUID magnetometry. Magnetizatio
n curves show the influence of the shape anisotropy of the wires. Zero fiel
d-cooled (ZFC) initial magnetic susceptibility measurements indicate a rang
e of blocking temperatures which extends at least to room temperature, sugg
esting the presence of some relatively large Co-rich clusters. A sharp rise
in the ZFC susceptibility for the smallest diameter wires at temperatures
below about 20 K suggests that in these wires there are also some extremely
small clusters present. (C) 2000 Elsevier Science B.V. All rights reserved
.