Giant magnetoresistance and domain observation of Co<inf>35</inf>(SiO<inf>2</inf>)<inf>65</inf> nano-granular film

Abstract

A series of Co35(SiO2)65 (volume fraction) nano-granular films with different annealing temperature (TA) were fabricated using ion-beam sputtering technique. A giant magnetoresistance of about 4% at room temperature was observed. The transmission electronic microscopy (TEM) observation shows clearly isolated nano-scale cobalt particles embedded in the SiO2 matrix. A magnetic force microscopy (MFM) was used to image the topography and magnetic microstructures of Co35(SiO2)65 nano-granular film. The domains were resolved clearly on MFM micrographs with much larger size (about 10-20 nm) than that of cobalt particles (about 1-2 nm) in the annealed samples, which demonstrated that there may be interparticle correlation among many of the isolated single-domain cobalt particles.