Structural and magnetic characterization of Fe-Ga thin films sputter-deposited on Si wafers and optical fibers

Galfenol (Fe-Ga alloys) thin films were sputter-deposited on different substrates, i.e. Si(100) wafers and glass optical fiber Bragg gratings in different deposition configurations, with the substrates rotating either parallel or perpendicular to the single Fe-Ga target. Structural characterizations by XRD, EDS and SEM revealed that Fe-Ga thin films have a columnar structure whose orientation depends both on the experimental conditions during deposition and on the geometry of the substrate. The Fe-Ga films with a thickness larger than 1 mu m predominantly showed a body-centered cubic (alpha-Fe) A2 phase and a (111) growth orientation in both types of substrates considered in this work. Magnetic characterizations by hysteresis loops and FORCs demonstrated that the films contain magnetic single and multi-domains which interact with each other to some extent.