Dynamic Magneto-mechanical Behavior of an Iron-nickel-based Ferromagnetic Alloy with Constant Elasticity

Abstract

The dynamic magneto-mechanical behaviors in a type of iron-nickel-based ferromagnetic alloy with constant elasticity were investigated as a function of both the DC bias magnetic field (<TEX>$H_{dc}$</TEX>) and the frequency. The rectangular plate-like samples were excited to vibrate at a half-wavelength, longitudinal resonance by an AC magnetic field superimposed with various <TEX>$H_{dc}$</TEX>. The experimental results found that the strain coefficient at resonance reached 819.34 nm/A and the effective mechanical quality factor (<TEX>$Q_m$</TEX>) was greater than 2000. The ratio of the maximum variation of the Young's modulus over <TEX>$H_{dc}$</TEX> to the value of the Young's modulus at a zero bias field was only <TEX>${\sim}0.83%o$</TEX> because of the so-called constant elasticity. The resonant strain coefficients and <TEX>$Q_m$</TEX> are strongly dependent on <TEX>$H_{dc}$</TEX>, which indicates a promising potential for use in DC and quasistatic magnetic field sensing.