Investigation of power generation mechanism and anisotropy of Fe–Ga magnetostrictive alloy single crystal based on magnetic domain observations

Abstract

Recent developments in the field of vibration-based power generators have highlighted the advantages of using Fe–Ga alloys; these are excellent-magnetostrictive materials having good mechanical properties, which makes them well suited for use as magnetostrictive elements. A rectangular Fe–Ga element oriented along the 〈100〉 direction in a U-shaped unimorph device produces a higher power generation efficiency than samples with other orientations such as 〈110〉 and 〈111〉. The crystal growth direction of the ingots and plane orientation of the elements have a minimal effect on the power-generation efficiency. The observations of the magnetic domain and elastic properties suggest that the anisotropy in power generation is attributable to the anisotropic magnetic and elastic properties of the Fe–Ga alloy. Thus, a high-performance, vibration-based power generator using the Fe–Ga alloy should be fabricated using elements with a 〈100〉 orientation, cut from a single-crystal Fe–Ga ingot.