The magnetoelastic properties of laves-phase TbxHo0.9-xNd0.1Fe1.8Mn0.1 compounds: An in-situ Lorentz microscope study

Magnetocrystalline anisotropy and magnetic field-driven magnetic domain movement have significant influences on magnetoelastic properties. In this work, polycrystalline TbxHo0.9-xNd0.1Fe1.8Mn0.1 (0.08 ≤ x ≤ 0.25) compounds were prepared and the characteristics of these compounds were then investigated, i.e. magnetic domain walls, magnetocrystalline anisotropy compensation and magnetostriction. The experimental results suggest that the easy magnetisation direction (EMD) lies towards the <100> axis for x ≤ 0.08 and the <111> axis for x ≥ 0.15. The EMD is further confirmed, for the first time, by an electron holography (EH) technique. Additionally, the relationship between the difficulty of domain walls motion and the magnitude of magnetocrystalline anisotropy was investigated by in-situ Lorentz transmission electron microscopy (LTEM). For the Tb0.15Ho0.75Nd0.1Fe1.8Mn0.1 compound, a large low-field induced magnetostriction, e.g. λa ∼ 322 ppm at 2 kOe, was obtained. This work can help to understand the effects of magnetocrystalline anisotropy on magnetostrictive properties for the rare earth-transition metal Lave-phase materials.