Estudo da magnetoimpedância gigante e do efeito hall em fitas amorfas de Co70.4 Fe4.6 Si15 B10.

Abstract

This work presents a study of giant magneto impedance and Hall effect measurements in amorphous ribbons of the zero-magnetostriction soft-ferromagnet Coyo^Fe^SiisBio alloys. It was demonstrated the existence of a giant transversal magneto-impedance effect (GTMI) in pieces of this ribbons. The magnetic field dependence of the GTMI shows a peak which is strongly dependent on frequency and on amplitude of the curret applied in the measurements. It reaches the giant value of 28% at H = 350Oe for f = 100kHz and he = 25mA. The Hall effect yielded a value of Rs = 0.43/^Q- cm • kOe'1 _ Peaks which are also frequency dependent were observed at the Hall voltage. The giant magneto impedance in these ribbons can be highly enhanced by varying the sample length, the annealing temperature, and the magnitude of the eletrical alternated current. This work also presents the possibility of using the GMI effect in the construction of pressure sensor.