Galfenol-based devices for magnetic field sensing in harsh environments

This paper presents a new concept of magnetic field sensor, employing a magnetostrictive active material and a strain sensor based on a fiber Bragg grating (FBG). The integration of the FBG with the magnetostrictive alloy, allows the transduction of the field signal into a wavelength shift of the FBG. Such an approach allows reliable and multipoint measurements also in harsh environments. Unlike a similar approach [6], the proposed concept sensor employ a Fe-Ga alloy (Galfenol), presenting better performances in terms of rate-independent memory effects (hysteresis) and this would avoid complex procedures for the field reconstruction. Moreover, the possibility to produce samples with frozen prestress in the material, would also allow a better tailoring of the active material with respect to the required sensor characteristics.