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 (m(g 33)) exhibited a flat response with frequency, except for the variation associated with the fundamental shape resonance of the samples at about 46 kHz. Both m(T)(r)(33) (at constant stress) and m(s)(r)(33) (at constant strain) reached their maximum values at a magnetic bias field (H-Bias) of about 20kA/m due to the relatively easy 180D domain-wall motion. The two elastic moduli, E-H(3) (at constant magnetic field strength) and E-3(B) (at constant magnetic flux density), showed a small decrease with increasing H-Bias with no trace of negative - U E effect in the H-Bias range of 5-240 kA/m. The saturation magnetostriction (l(S)) was not attained at the highest available field level, reflecting the existence of relatively high magnetocrystalline anisotropy in the material. The dynamic strain coefficient (d(33)) displayed a broad negative maximum around H-Bias = 180kA/m as a result of the maximum motion of non-180D domain walls. C 2004 Elsevier B.V. All rights reserved.