Patent ID: 7088247

Claim:
A resonator for use in a marker in a magnetomechanical electronic article surveillance system, said resonator comprising: a planar strip of an amorphous magnetostrictive alloy having a longitudinal axis and having a composition comprising at least iron and nickel and at least one element from the group consisting of Groups Vb and VIb of the periodic table, and being annealed at an elevated temperature while being subjected to a tensile force along said longitudinal axis so that said planar strip has an induced magnetic easy plane perpendicular to said longitudinal axis, and having a resonant frequency f r when driven by an alternating signal burst in an applied bias field H, a linear B—H loop up to at least an applied bias field H of about 8 Oe, a susceptibility |df r /dH| of said resonant frequency f r to said applied bias field H which is less than about 1200 Hz/Oe, and a ring-down time of the amplitude to 10% of its value after the signal burst ceases which is at least about 3 ms for a bias field where the amplitude 1 ms after said alternating signal burst ceases has a maximum.