A magnetostrictive biased magnetic field sensor with geometrically controlled full-scale range

A magnetic field sensor prototype is developed and tested in this work. The device exploits a Galfenol rod, i.e. a giant magnetostrictive Iron-Gallium alloy, integrated with a Fiber Bragg Grating. In particular, the full-scale range of the sensor can be modulated through the exploitation of the geometrically dependent effect of the demagnetizing field. Indeed, it pushes toward higher fields the magnetic saturation by producing a sort of magnetic shield in the material. As a consequence, the geometrical viewpoint is included into the frame of the entire design process, with the aim of investigate how it influences the detectability range and the performance of the sensor. Furthermore, a permanent magnet system providing a DC bias magnetic field has been designed and exploited to allow the device to be able to measure both negative and positive magnetic fields.