High-performance vibration power generation using polycrystalline Fe–Co-based alloy due to large inverse magnetostrictive effect

S Inoue,T Nakagawa,S Hashi,S Seino,F Osanai,K Ishiyama,T Okada,T A Yamamoto,S Fujieda,S Suzuki

doi:10.1063/5.0038903

Abstract

The magnetic flux density change ΔB caused by the inverse magnetostrictive effect is key for achieving high-performance vibration power generation. As the magnetization curve of the polycrystalline Fe–47.6 at. % Co–2.3 at. % V (Fe–Co–V) alloy became easier to magnetize by applying tensile stresses, the value of ΔB estimated from the magnetization curves depended significantly on magnetic fields. Hence, the vibration power generation of a U-shaped unimorph device using a polycrystalline Fe–Co–V alloy core was demonstrated under various bias magnetic fields. As a result of bias magnetic field adjustment, the open-circuit voltage induced by the vibration of the device improved to ∼7.0 V. Such superior performance is attributable to a large ΔB of 1.1 T in the Fe–Co–V alloy core. Therefore, adjustment of bias magnetic fields is essential for obtaining large ΔB in Fe–Co–V alloys, which are promising inverse magnetostrictive materials for high-performance vibration power generation.

Highlights

An Fe–50 at. % Co alloy has been demonstrated to exhibit a large saturation magnetization of 2.35 T,16 the magnetostriction constant of the former is smaller than those of Fe–Ga alloys.17 Some research groups have investigated devices using Fe–Co alloys or their composites.18–22 their results do not obtain a 1% magnetic flux density change in saturation magnetization.18–21 In this study, the enhancement of magnetic flux density change due to the inverse magnetostrictive effect of a polycrystalline Fe–47.6 at. % Co–2.3 at. % V (Fe–Co–V) alloy was investigated
As the magnetization curve of the polycrystalline Fe–47.6 at. % Co–2.3 at. % V (Fe–Co–V) alloy became easier to magnetize by applying tensile stresses, the value of ΔB estimated from the magnetization curves depended significantly on magnetic fields
The vibration power generation of a U-shaped unimorph device using a polycrystalline Fe–Co–V alloy core was demonstrated under various bias magnetic fields

Summary

Introduction

An Fe–50 at. % Co alloy has been demonstrated to exhibit a large saturation magnetization of 2.35 T,16 the magnetostriction constant of the former is smaller than those of Fe–Ga alloys.17 Some research groups have investigated devices using Fe–Co alloys or their composites.18–22 their results do not obtain a 1% magnetic flux density change in saturation magnetization.18–21 In this study, the enhancement of magnetic flux density change due to the inverse magnetostrictive effect of a polycrystalline Fe–47.6 at. % Co–2.3 at. % V (Fe–Co–V) alloy was investigated. The magnetic flux density change ΔB caused by the inverse magnetostrictive effect is key for achieving high-performance vibration power generation. The vibration power generation of a U-shaped unimorph device using a polycrystalline Fe–Co–V alloy core was demonstrated under various bias magnetic fields.

Results

Conclusion