Magnetoelastic properties of polymer-bonded Sm0.88Dy0.12Fe1.93 pseudo-1-3 composites

Pseudo-1-3 magnetostrictive composites of approximately 0.6 volume-fraction Sm0.88Dy0.12Fe1.93 particles and epoxy were fabricated, and their quasi-static and dynamic magnetoelastic properties were investigated. The dynamic relative permeability (μr33) exhibited a flat response with frequency, except for the variation associated with the fundamental shape resonance of the samples at about 46 kHz. Both μr33T (at constant stress) and μr33S (at constant strain) reached their maximum values at a magnetic bias field (HBias) of about 20 kA/m due to the relatively easy 180° domain-wall motion. The two elastic moduli, E3H (at constant magnetic field strength) and E3B (at constant magnetic flux density), showed a small decrease with increasing HBias with no trace of negative-ΔE effect in the HBias range of 5-240 kA/m. The saturation magnetostriction (λS) was not attained at the highest available field level, reflecting the existence of relatively high magnetocrystalline anisotropy in the material. The dynamic strain coefficient (d33) displayed a broad negative maximum around HBias=180kA/m as a result of the maximum motion of non-180° domain walls.