Dynamic magnetoelastic properties of epoxy-bonded Sm₀. ₈₈Nd₀.₁₂Fe₁.₉₃ pseudo-1-3 negative magnetostrictive particulate composite

Abstract

Pseudo-1-3 negative magnetostrictive particulate composite is prepared by embedding and aligning light rare earth (Sm and Nd)-based negative magnetostrictive Sm₀. ₈₈Nd₀.₁₂Fe₁.₉₃ particles with randomly distributed sizes of 10–180 μm in a passive epoxy matrix using a particle volume fraction of 0.5. The dynamic magnetoelastic properties of the composite are investigated as a function of both magnetic bias field and frequency under a constant magnetic drive field. The dynamic relative permeability (μ[sub r]₃₃) exhibits a flat frequency response with no observable dispersion at all bias field levels, except for the fundamental shape resonance range of 40–50 kHz. The free (μ[sub r]₃₃[sup T]) and clamped (μ[sub r]₃₃[sup S]) relative permeabilities attain their maximum values at low bias field levels of ≤10 kA/m because of the relatively easy 180° domain-wall motion. The elastic modulus at constant magnetic field strength (E₃[sup H]) and that at constant magnetic flux density (E₃[sup B]) show a maximum negative-ΔE effect, accompanying a maximum dynamic strain coefficient (d₃₃) of −2 nm/A, at about 100 kA/m due to the maximum motion of non-180° domain walls.