Electrodeposited, GMR CoNiFeCu Nanowires and Nanotubes from Electrolytes Maintained at Different Temperatures

Nanowires and nanotubes with modulated composition to realize a magnetoresistance effect were potentiostatically electrodeposited into alumina nanoporous templates. The multilayers were modulated between a Co-rich alloy and a Cu layer. The structure was characterized by electron microscopy. Deposits obtained from room temperature and 50 degrees C electrolytes were nanowires, and a giant magnetoresistance (GMR) of up to 20% was observed. Chilling the electrolyte to 4 degrees C resulted in nanotubes with a modulated structure. The current-potential behavior was examined with voltammetry and pulse transients. As expected, the cathodic current density increases with electrolyte temperature, although less obvious is the unfavorable anodic component, resulting during the transition between depositing the magnetic layer and a copper layer, which changes with time and differs with variable electrolyte temperature. (C) 2010 The Electrochemical Society. (DOI: 10.1149/1.3365055) All rights reserved.