Abstract
A process for producing a dispersion of nanometer-sized, Co-rich particles embedded in a thin film of Cu-rich matrix is presented. Thin films were prepared by thermal evaporation of a bulk CoCu alloys on an amorphous C substrate. In situ transmission electron microscopy (TEM) and field-emission gun TEM equipped with an energy dispersive x-ray spectrometer were used to investigate spinodal decomposition of the initial homogeneous thin film alloy. The maximum giant magnetoresistance (GMR) is found to be 18% for a Co45Cu55 after heating the film from room temperature at 2 degrees C/min to 204 degrees C and holding for 10 min. These nanostructures are expected to exhibit optimum GMR for granules having higher Co content. (c) 2006 American Institute of Physics.