Giant magnetoresistance in Cu–Co films electrodeposited on n-Si

Abstract High quality Cu–Co alloy films with excellent metallic luster have been electrolytically deposited directly onto n-Si (1 0 0) substrate, thereby eliminating the need of a conducting seed layer, which is otherwise required when the films were grown on insulating substrates (Al 2 O 3 ). The as-deposited Cu–Co films exhibit relatively higher magnetoresistance (MR) in comparison with the as-deposited films on Al 2 O 3 under identical conditions. The observed increase in MR could be attributed to the reduced substrate current shunting. The MR further improves to 2.67% (at H =10 kOe) with vacuum annealing (at 425°C for 30 min) of the films on Si. This has been ascribed to the separation of Cu and Co phases resulting in a magnetic granular nanostructure. This value of MR of annealed films on Si is, however, lower in comparison with the value obtained for annealed films deposited on Al 2 O 3 . Glancing angle X-ray diffraction (GAXRD) has revealed the formation of copper silicide in these samples, which is responsible for the lower value of MR. Thus we have observed good MR with a copper silicide host matrix.