Structure–Property Correlations in CoFe–SiO 2 Nanogranular Films Utilizing x-Ray Photoelectron Spectroscopy and Small-Angle Scattering Techniques

A quantitative structure–property correlation study of thin films consisting of CoFe nanoparticles embedded in SiO2 is presented, comparing film microstructure and chemistry with measured magnetic properties. SiO2 was fully percolated for all films with > ~50% SiO2 by volume, and decreasing CoFe-nanoparticle size and separation with increasing SiO2 resulted in a transition to superparamagnetic behavior. Partial oxidation of transition-metal elements is observed by x-ray photoelectron spectroscopy, and evidence for interparticle magnetic interactions can be resolved in soft x-ray resonant small-angle scattering experiments, highlighting the need for additional detailed and quantitative studies in this class of soft magnetic materials.