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 similar to 0.8 parts per thousand 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.