Anisotropy compensation and high low-field magnetostriction of epoxy/Tb1−xHox(Fe0.8Co0.2)2 composites (0.60 ≤ x ≤ 1.0)

The anisotropy compensation and magnetostrictive properties of Tb1−xHox(Fe0.8Co0.2)2 (0.60 ≤ x ≤ 1.0) alloys have been investigated. The easy magnetization direction (EMD) at room temperature rotates from the 〈1 1 1〉 axis (x ≤ 0.75) to the 〈1 0 0〉 axis (x ≥ 0.90) through an intermediate state 〈1 1 0〉, subjected to the anisotropy compensation between Tb3+ and Ho3+ ions. Composition anisotropy compensation is realized near x = 0.75. The Tb0.25Ho0.75(Fe0.8Co0.2)2 alloy has a minimum anisotropy and a large spontaneous magnetostriction coefficient λ111 (≈740 ppm) at room temperature. The strong 〈1 1 1〉-oriented 1-3 epoxy-bonded composite has been fabricated by curing under a moderate magnetic field. A high low-field magnetostriction of about 400 ppm at 3 kOe is obtained for the 1-3 epoxy/Tb0.25Ho0.75(Fe0.8Co0.2)2 composite with 40-vol% alloy particles, which can be attributed to the low magnetic anisotropy, EMD lying along 〈1 1 1〉 direction, the strong 〈1 1 1〉-textured orientation and the chain structure.

► Anisotropy compensation has been realized for the Tb1−xHox(Fe0.8Co0.2)2 alloys.
► The 〈1 1 1〉-oriented 1-3 epoxy-bonded composite has been fabricated.
► A high low-field magnetostriction (400 ppm at 3 kOe) is obtained for the composite.