Magnetostriction of TbxDy0.9−xNd0.1(Fe0.8Co0.2)1.93 compounds and their composites (0.20 ⩽ x ⩽ 0.60)

The structure, spin configuration, magnetocrystalline anisotropy compensation, magnetic properties, and magnetostriction of TbxDy0.9−xNd0.1(Fe0.8Co0.2)1.93 (0.20 ⩽ x ⩽ 0.60) alloys are investigated. The easy magnetization direction (EMD) at room temperature rotates from the 〈1 0 0〉 axis (x ⩽ 0.25) to the 〈1 1 1〉 axis (x ⩾ 0.30) with increasing Tb content, subjected to the anisotropy compensation between Tb3+ and Dy3+ ions. The analysis of X-ray diffraction, EMD and magnetostriction show that TbxDy0.9−xNd0.1(Fe0.8Co0.2)1.93 is an anisotropy compensation system and the compensation point is realized around x = 0.30. The Laves phase compound Tb0.4Dy0.5Nd0.1(Fe0.8Co0.2)1.93 has a large spontaneous magnetostriction, the coefficient λ111 up to about 1640 ppm. The epoxy bonded 0-3 and pseudo-1-3 composites were fabricated by curing without and with a magnetic field. A high magnetostriction, longitudinal λ|| and linear anisotropic λa(= λ||−λ⊥) up to around 390 and 650 ppm at 6 kOe, respectively, is obtained for the grain 〈1 1 1〉-oriented pseudo-1-3 epoxy/Tb0.4Dy0.5Nd0.1(Fe0.8Co0.2)1.93 composite with 20 vol% alloy particles.