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

The spin configuration and spontaneous magnetostriction lambda(111) 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 lambda(111), 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, lambda(a), 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., lambda(111) not equal lambda(100), < 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. (C) 2015 AIP Publishing LLC.