Affiliations: [a] Istituto Nazionale per la Fisica della Materia (INFM),
Dip. di Scienze Fisiche, Università "Federico II", P.le V.Tecchio 80, 80125
Napoli, Italy
Abstract: The effect of a silicone sheathing on the static and dynamic
magnetoelastic properties of an amorphous ferromagnetic ribbon were
experimentally investigated and some simple modelling of the detected behaviour
are reported. Since silicone sheath and ferromagnetic ribbon do not form alloy,
it is shown that internal friction between the two component has a determining
role. In the presence of static friction, magnetisation and magnetoelastic wave
amplitude are prevented by the silicone sheath; but after a threshold values of
the magnetising field a dump occurs towards more easy magnetisation or higher
amplitude of oscillations (in resonance condition), respectively. The
magnetisation curve represents a step by crossing the threshold magnetising
field value; this step is very flat so that it can be used for sensors of a
little magnetic field change or as switch activated by little magnetic field
input. For what concerns the application of this two component material as
resonator core it can be deduced that, also when a silicone sheath is present,
the amplitude of resonant magnetoelastic wave is a good detector of stress,
strain or local magnetic field; so that the application of magnetoelastic
resonators made by amorphous ribbon core may be expanded to the cases which
require a protection covering, as for example when it is necessary to work in
water or in the human body.
