Effect of heat-treatment on magnetostriction in <110> oriented crystals Tb_0.36Dy_0.64 (Fe_0.85Co_0.15)₂

<110> oriented crystals Tb_0.36Dy_0.64 (Fe_0.85Co_0.15)₂ were prepared through zone melting unidirectional solidification. A homogenization annealing for 4 h at 1000°C and a magnetic annealing under 240 kA/m were carried out on the rod-shaped samples. The orientations, morphologies and magnetostriction of the Tb_0.36Dy_0.64 (Fe_0.85Co_0.15)₂ rods with unidirectional solidification, homogenization, and magnetic annealing were investigated, respectively. It is found that the magnetostriction can be improved effectively through homogenization annealing, due to the spheroidal variation of the pseudo-eutectic rare-earth-rich phase. The magnetostriction measured under free conditions is significantly improved after magnetic annealing, while the jump effect under a uniaxial compressive stress becomes weaker. The redistribution of the initial moments is suggested to be responsible for this change.