MAGNETOSTRICTIVE ELEMENT HAVING OPTIMIZED BIAS-FIELD-DEPENDENT RESONANT FREQUENCY CHARACTERISTIC

摘要

A magnetostrictive element for use in an magnetomechanical marker has aresonant frequency characteristic that is at a minimumat a bias field level corresponding to the operation point of themagnetomechancial marker. The magnetostrictive element has amagnetomechanical coupling factor k in the range 0.28 to 0.4 at the operatingpoint (26). The magnetostrictive element is formed byapplying current-annealing to an iron-nickel-cobalt based amorphous metalribbon, or by cross-field annealing an iron-nickel-cobalt alloythat includes a few percent chromium and/or niobium.