Strain Modulation of Microstructure, Magnetic Domains, and Magnetic Properties of Ti/Fe/Ni81Fe19/Fe/Ti Multilayer Thin Films

A simple and convenient method is demonstrated in this work by continuously applying uniaxial tensile strains to tune the high-frequency properties of flexible magnetic films. The magnetostriction effect causes the uniaxial magnetic anisotropy in the Ti/Fe/Ni81Fe19/Fe/Ti multilayer film when the flexible substrate transitions from the convex state to the planar state after preparation. In addition, the microstructure, magnetic domain morphology, and the high-frequency magnetic performance of the pre-strained Ti/Fe/Ni81Fe19/Fe/Ti multilayer films are investigated. The results show that the flexible Ti/Fe/Ni81Fe19/Fe/Ti multilayer films' initial permeability can be monotonically varied over a hundred units, and the resonant frequency can be adjusted around 1.5 GHz. The flexible Ti/Fe/Ni81Fe19/Fe/Ti films, with their elastic-tunable magnetic performance, are promising candidate materials for flexible microwave devices.