Enhanced magnetostrictive effect in epoxy-bonded TbxDy0.9-xNd0.1(Fe0.8Co0.2)1.93 pseudo 1-3 particulate composites

Abstract

The spin configuration and spontaneous magnetostriction λ111 of TbxDy0.9-xNd0.1(Fe0.8Co0.2)1.93 (0.20 ≤ x ≤ 0.60) alloys have been investigated. The easy magnetization direction (EMD) at room temperature was observed towards the '111' axis when 0.40 ≤ x ≤ 0.60, accompanied by a rhombohedral distortion with large spontaneous magnetostriction coefficients λ111, which increases from 1640 ppm for x = 0.40 to 1900 ppm for x = 0.60. The strong '111'-oriented pseudo 1-3 particulate composite was fabricated by embedding and aligning particles in a passive epoxy matrix under an applied magnetic field. An enhanced magnetostrictive effect, the large low-field magnetostriction, λa, as high as 480 ppm at 3 kOe, was obtained for the sample of x = 0.40, in an excess of 75% of its polycrystalline alloy although it only contains 27 vol. % alloy particles. This enhanced effect can be attributed to its low magnetic anisotropy, anisotropic magnetostrictive nature (e.g., λ111 ≈ λ100, '111'EMD), chain structure, and the '111'-textured orientation. In addition, we give a direct experimental support that the '111'EMD of particle and the strong '111'-textured orientation are the crucial factors to realize the enhanced magnetostrictive effect in 1-3 particulate composites.