Growth of giant magnetoresistance metallic granular Co-Ag films by pulsed laser deposition

Giant magnetoresistance in pulsed-laser-deposited single layers of Co-Ag heterogeneous alloys is investigated. The as-deposited Co0.30Ag0.70 films exhibit phase segregation, and a 27% magnetoresistance value at 4.2 K under a magnetic field of 4.7 T. The magnetoresistance behaviour is found to be strongly sensitive to the film composition and preparation conditions, particularly post-annealing, and can be attributed to the particle size effect. Thus the optimal choice of parameters to maximise the magnetoresistance can be determined.