This thesis is concerned with the magnetic properties of magnetostrictive FeSiBC amorphous films based on the METGLAS^® 2605SC composition; the films have been produced by RF magnetron sputtering. The ribbon form of the material has excellent magnetic properties, which are ideal for magnetic thin film sensors. The deposition of films is a complex process which is strongly dependent upon many parameters; these are discussed and investigated in detail in this thesis. It has been demonstrated that it is possible to produce FeSiBC films with magnetic properties comparable to those of the original METGLAS^® 2605SC ribbon material used as the sputtering target. The magnetic properties were principally investigated using the magneto-optical Kerr effect, with both point hysteresis measurements and domain imaging. These measurements were made using equipment which was constructed during the course of this present work.

A significant, reproducible in-plane radial anisotropy was observed in the as-deposited films, which was attributed to the residual field produced by the magnetron sputter source. The effects of various treatments on the samples were investigated, including the use of forming fields, stress and thermal processing. The deliberate introduction of stress into these materials is found to allow excellent control of both the direction and magnitude of the magnetic anisotropy. A high degree of control is demonstrated in tailoring the anisotropy field, using the technique of stress annealing. The treatments are evaluated for their potential to enable the magnetic anisotropy in magnetostrictive device applications to be controlled.

A simple new technique is described for the measurement of saturation magnetostriction in thin films deposited onto rigid substrates. The method is based on mechanically introducing a small curvature into the substrate. The strain induced anisotropy is measured using the magneto-optical Kerr effect. Quantification of the film strain is obtained using optical interference and stylus measurements; this allows the saturation magnetostriction to be determined. No information about the mechanical properties of the substrate is required and, providing that the Young’s modulus of the film is known accurately, the values of magnetostriction obtained are accurate and absolute. It is envisaged that the technique could be applied to a wide variety of films deposited onto commercially important substrates.

The possibility of using magnetostrictive FeSiBC films as Magneto Impedance sensors has also been investigated.