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

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 ($H_dc$) 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 $H_dc$. The experimental results found that the strain coefficient at resonance reached 819.34 nm/A and the effective mechanical quality factor ($Q_m$) was greater than 2000. The ratio of the maximum variation of the Young's modulus over $H_dc$ to the value of the Young's modulus at a zero bias field was only ${\sim}0.83%o$ because of the so-called constant elasticity. The resonant strain coefficients and $Q_m$ are strongly dependent on $H_dc$, which indicates a promising potential for use in DC and quasistatic magnetic field sensing.