Magnetic and Structural Properties of Granular Iron-Silicon Dioxide Thin Films

Abstract

ABSTRACTFe-SiO2 granular films were produced by co-sputtering from separate Fe and SiO2 targets. Films deposited on silicon nitride membranes were thin enough to observe directly by transmission electron microscopy (TEM). The coercive force (Hc) was strongly dependent on temperature and volume fraction of Fe as observed in previous investigations, but with lower Hc. Two features of the films with low Fe concentrations were remarkable. The hysteresis loops show high remanence, and the room temperature TEM images show stable domain structure and ripple patterns. This behavior is inconsistent with a model of non-percolating, non-interacting superparamagnetic Fe grains.