Magnetism and magneto-transport studies in sonochemically prepared amorphous Co100−xPtx nano alloys

Bulk amorphous Co(100−x)Ptx (0≤x≤50) nano-alloys have been synthesized using high frequency ultrasound, displaying single domain (4–5 nm) behavior wherein weakly exchange-coupled particles lead to a field-dependent resistivity behavior. Magneto-resistivity is correlated to the order–disorder parameter in these powder compacts. The plot of Δρ/ρ0 as a function of reduced magnetization indicates that all the systems are weakly exchange coupled.