5th INTERNATIONAL WORKSHOP ON ELECTRODEPOSITED NANOSTRUCTURES 7-9 June 2007, Iasi, Romania	ABSTRACTS

Nanowires with magnetic properties fabricated using the template approach Ionut Enculescu National Institute for Materials Physics, P.O.Box MG 7, 77125 Magurele, Ilfov, Romania E-mail: encu@infim.ro In the last decade, the field of preparation of materials with low dimensionality and the investigation of their properties attracted more and more scientists. The reason for such an increase was given by the wide range of applications, starting from electronics information and communications industry to medicine and biology or textiles industry. The key feature of nanostructures when compared with their bulk counterparts it is not given only by miniaturization of devices but consists in the strong change in properties induced by the low dimensionality and high surface to volume ratio. The template approach represents an interesting path towards preparation of nanoobjects with controlled morphological properties mainly due to the fact that by appropriate choosing of host templates the shape and dimension of the prepared structures are precisely determined. A type of templates which is widely used for such experiments is the nanoporous membranes. Most of the studies reported in literature are based on two types of such membranes: polymer ion track membranes and anodic alumina. Both present a number of advantages which makes them suitable for the fabrication of high aspect ratio nanostructures, namely nanowires and nanotubes. The method of filling of the pores for such membranes, thus of fabricating the nanostructures, are various but by far the most employed one is electrochemical deposition. Based on the knowledge gained in the case of thin films, electrodeposition was mainly employed for the preparation of metallic nanowires but also semiconductor nanowires are prepared using such an approach. Electroless deposition was also used connected to nanoporous membranes allowing the preparation of hollow structures in contrast with electrochemical deposition which leads in most of the cases to rod-like deposits. The present report will be focused on electrochemical deposition of nanowires and nanotubes with magnetic properties. In the first part it will be presented the electrochemical deposition in a single-nanopore membrane followed by subsequent sputtering of a second conductive electrode, to fabricate and reliably contact single nanowires consisting of Cu/Co multilayers and Co-Cu alloy respectively. With this technique no further manipulation of the wires and no lithographical processes are necessary. The contacts are very stable, stand high current densities, and enable both long-term storage of the samples and transport between laboratories. Single nanowires embedded in polymer matrix may be also suitable for commercial production of single-nanowire magnetic field sensors. A second subject will be related to the preparation of nano and micro-tubes of nickel using the electroless deposition from an acidic bath using polycarbonate ion track membranes as templates. The preparation of ZnO:Mn:Cu nanowire arrays by cathodic electrodeposition from aqueous solution, using as template a polycarbonate membrane will be presented as an example of the possibilities opened by electrochemistry in the fabrication of nanostructured semiconductors containing magnetic impurities.

 
 
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