Magnetomechanical properties of epoxy-bonded (Tb_0.3Dy_0.7)_1-xPr_xFe_1.55(0 ≤ x ≤ 0.4) pseudo-1-3 magnetostrictive composites

Pseudo-1-3 magnetostrictive composites consisting of stabilizer (B, Co)-free, light rare earth (Pr)-containing magnetostrictive (Tb0.3Dy0.7)1-xPrxFe1.55(0 ≤ x ≤ 0.4) particles with a size distribution of 10-300 νm embedded and aligned in a passive epoxy matrix using 0.5 volume fraction are fabricated. The quasistatic magnetomechanical properties of the composites are investigated and compared with their monolithic (Tb0.3Dy0.7)1-xPrxFe1.55alloys, as a function of the Pr content x. The composites show similar qualitative trends in properties with the alloys for all x. The (Tb0.3Dy0.7)0.75Pr0.25Fe1.55composite and alloy exhibit the smallest coercivity Hc, the largest magnetostriction λ and the highest piezomagnetic coefficient d33due to the successful compensation for magnetocrystalline anisotropy. The (Tb0.3Dy0.7)0.75Pr0.25Fe1.55composite demonstrates a large saturation magnetostriction λsof 793 ppm at 700 kA m-1and a high d33of 3.2 nm A-1at 140 kA m-1. These values approach 81% and 85% of its alloy values at the same field levels. The good properties make the (Tb0.3Dy0.7)0.75Pr0.25Fe1.55composite and alloy a promising magnetostrictive material system.