Attenuation of magnetic effects in soft amorphous ribbons

Magnetization reversals taking place in ferromagnetic materials can be detected using pickup coils wrapped around the sample, the so-called Barkhausen noise. The voltage peaks induced in the coils depends both on the value ΔM of each magnetization reversal and on the attenuation V (x) of the inductive signal after travelling a distance x inside the material. Here we present a procedure for obtaining V (x) starting from the Barkhausen noise induced in two pickup coils separated by a distance variable between 2 and 40 mm. This procedure starts from the experimental values of R, the ratio of the signals induced in coincidence by the same magnetization reversal in the two coils, measured in a thin amorphous ribbon of Fe63B64Si8Ni15. Working with the signal ratio allows to get rid of the dependency on ΔM. A mathematical model for extracting V (x) from the histogram of the measured values of R is presented.