Magnetic Force Microscopy: A Powerful Tool to Image Domain Structures in Granular Thin Films

Abstract

Magnetic force microscopy was used to study the long-range domain structures appearing in rf-sputtered giant magnetoresistive CoFe-NM granular thin films (NM = Ag, AgCu). Even all samples were granular and the ferromagnetic concentration was far below the volume percolation threshold, out-of-plane domain-like configurations much larger than the particle size were observed due to the magnetic correlations among the CoFe particles. A large variety of remanent microstructures were also imaged as a function of the thermomagnetic history.