Dynamic magnetomechanical properties of epoxy-bonded (Tb0.3Dy0.7)1-xPrxFe1.55 (0 ≤ x ≤ 0.4) pseudo-1-3 magnetostrictive composites

Pseudo-1-3 magnetostrictive composites of 0.5 volume fraction are fabricated by embedding and aligning stabilizer (B, Co)-free, light rare earth (Pr)-contained magnetostrictive (Tb_0.3Dy_0.7)_1-xPr_xFe_1.55 (0 ≤ x ≤ 0.4) particles with a size distribution of 10-300 μm in a passive epoxy matrix. The dynamic magnetomechanical properties of the composites with different Pr content x are investigated as a function of both bias field (=10-200 kA/m) and frequency (=25 Hz-70 kHz). The composites show similar qualitative trends in properties for all x with no frequency dispersion effect except for the resonance range. The dynamic relative permeability μ_{r 33}^T demonstrates a decreasing trend with increasing x for the whole range of bias field due to the weakening of saturation magnetization with increasing Pr content. The two elastic moduli E₃^H and E₃^B, which result in negative-ΔE with maximum dynamic strain coefficient d₃₃ and dynamic magnetomechanical coupling coefficient k₃₃ near 140 kA/m bias in all composites, decrease with increasing x for all biases owing to the increasing compliance contribution from Pr. The (Tb_0.3Dy_0.7)_0.75Pr_0.25Fe_1.55 composite exhibits the largest d₃₃ and k₃₃ at 140 kA/m bias as a result of the compensation for magnetocrystalline anisotropy.