A new magnetoelastic device for sensing applications

In this paper a new magnetostrictive delay line set-up for sensor applications is proposed. The tri-layer set-up consists of an inner cylindrical copper core, an intermediate thin insulating layer and an outer circumferential magnetoelastic thin film. Packaging reasons require a coating-insulating layer on top of the set-up. Different Fe–Ni compositions have been tested for the magnetostrictive film. Characterization of the devices showed that negative magnetostrictive film operates as a magnetostrictive delay line set-up, even without magnetic and heat treatment. Concerning positive magnetostrictive films, heat treatment was necessary to allow the propagation and detection of the elastic pulses.