GIANT TRANSVERSAL MAGNETOIMPEDANCE AND HALL-EFFECT MEASUREMENTS IN CO70.4FE4.6SI15B10

We report room-temperature transversal magnetoimpedance (TMI) and Hall -effect measurements performed in ribbons of the zero-magnetostriction soft-ferromagnet Co70.4Fe4.6Si15B10 alloy annealed at 587 K for 15 mi n at a de magnetic field of 2 kOe. The annealing showed little effect on the magnetostriction of the samples. The frequency f and the amplit ude I-ac of the current used in the measurements, and the measuring ma gnetic field H were varied in the intervals 10 less than or equal to f less than or equal to 10(5) Hz, 2.5 less than or equal to I(ac)less t han or equal to 25 mA, and -15 less than or equal to H less than or eq ual to 15 kOe, respectively. The magnetic field dependence of the TMI shows a peak which is strongly dependent on f and on I-ac. It reaches the giant value of 28% at H=350 Oe for f=100 kHz and I-ac=25 mA. This TMI giant value is of the same order of the giant longitudinal magneto impedance (GLMI) but its peak is positioned in a magnetic field two or ders of magnitude larger than the value obtained for the GLMI. The Hal l effect yielded a value of R(S)=0.43 mu Omega cm kOe(-1). Peaks which are also frequency dependent were observed at the Hall voltage. (C) 1 996 American Institute of Physics.