We present an overview of our recent results on giant magnetoresistanc
e in as-prepared and annealed heterogeneous alloys obtained by sputter
ing or melt-spinning. Three series of alloys have been investigated: m
elt-spun CoxCu(1-x), sputtered NiFexAg(1-x) and sputtered (Co70Fe30)xA
g(1-x) alloys, with x between 5 and 40%.