Some important improvements in magnetostrictive piezoelectric sensors
have been obtained by applying an alternating current to the ferromagn
etic amorphous ribbon. First, we present a way to minimize the hystere
sis in these devices using a demagnetizing current through the magneti
c sample. Second, the current, at a frequency half that of the longitu
dinal piezoelectric resonance, is used to induce size changes in the h
igh-magnetostriction amorphous ribbon, and these changes, which depend
on the external magnetic held, can be read by the piezoelectric suppo
rt. Then, with this configuration, it is not necessary to have a coil
for the detection of a magnetic held.