Fabrication of Cu-Co nanogranular bulk materials by mixing of nanocrystalline powders

We show that nanogranular materials exhibiting moderate giant magnetoresistance can be prepared by mixing nanocrystalline powders of copper and cobalt. having grain size in a range of 40 nm. Nanopowders are mixed in various compositions using planetary ball mill and then sintered. Magnetoresistance (MR) is measured at 42 K and structural analysis are performed using X-ray diffraction. Variation of MR observed for various mixing conditions and cobalt contents are examined and discussed. This processing technique opens new perspectives for the fabrication of MR granular materials. (C) 2002 Elsevier Science B.V. All rights reserved,