Development of Metallic Soft Magnetic Materials for High-Frequency Driving Applications using Magnetoelastic Effect

Abstract

　This contribution introduces a fabrication method of Fe-Ni-system bilayer ribbons with positive and negative magnetostriction constants and improvement of soft magnetic properties using the magnetoelastic effect for high-frequency driving magnetic applications. We used an electroplating method to prepare a Fe₆Ni₉₄/Fe₅₆Ni₄₄ bilayer ribbon and measured the magnetic properties of a toroidal core with the ribbon. The shape of the hysteresis loop changed depending on the inner layer (inner magnetic phase), indicating that the induced anisotropy’s direction by the magnetoelastic effect changed depending on the inner layer. The increase in the coercivity over frequency was suppressed when the Fe₅₆Ni₄₄ layer was on the inner side, suggesting that controlling the anisotropy’s directions reduces eddy current losses. We conclude that a bilayer ribbon with different signs of magnetostriction constants is attractive for reducing coercivity (iron losses) under high frequency driving.