Generation and detection of magnetoelastic waves in partially annealed amorphous wires

A technique to improve the excitation and detection efficiency and to diminish the propagation loss of magnetoelastic waves in amorphous FeSiB wires is developed. Selected short portions of a cold drawn wire are annealed by Joule heat generated by current through them. The annealed, magnetically soft portions are used as excitation and detection sources of magnetoelastic waves and the as-quenched, hard portions are used as propagation paths. Optimum annealing conditions are experimentally obtained as a function of the length of the annealed portion. Larger annealing current is needed to anneal shorter portion. Magnetoelastic waves in the partially annealed wire are effectively excited and detected without bias magnetic field and they are hardly influenced by the surrounding field.