Effect of hydrogen absorption on magneto-resistance curves of GMR wire with Fe–Si–B/Pd layer

Abstract

In this study, we investigated the effect of hydrogen absorption on the magneto-resistance (MR) properties of giant magneto-resistance (GMR) wires with a hydrogen-absorptive Pd layer and a magnetostrictive Fe–Si–B layer. The hard-axis MR curves of Pd-coated GMR wires fabricated on a polyethylene naphthalate substrate changed significantly after H2 exposure. This result is explained by the isotropic lattice expansion of Pd and the geometrical shape of the GMR wire, defined by microfabrication, indicating that mechanical stress was directionally exerted along the length of the wire. We successfully demonstrated that hydrogen can be detected based on changes in the MR properties of GMR wire, which can be fabricated at low cost using lithography techniques.