Current effects in magnetostrictive piezoelectric sensors

Some important improvements in magnetostrictive piezoelectric sensors have been obtained by applying an alternating current to the ferromagnetic amorphous ribbon. First, we present a way to minimize the hysteresis in these devices using a demagnetizing current through the magnetic sample. Second, the current, at a frequency half that of the longitudinal piezoelectric resonance, is used to induce size changes in the high-magnetostriction amorphous ribbon, and these changes, which depend on the external magnetic field, can be read by the piezoelectric support. Then, with this configuration, it is not necessary to have a coil for the detection of a magnetic field.