Directional growth of polycrystalline magnetostrictive TbxDy1−xFey compounds by casting in a strong unidirectional gradient

International audience; Rods of highly magnetostrictive polycrystalline TbxDy1-xFey materials are elaborated by casting in a cylindrical mould with cooling imposed from the bottom which leads to a fast vertical unidirectional growth. A [1 1 0] orientation is obtained along the axis of the rods parallel to the growth direction. The magnetostrictive properties are remarkable along the rods axis comparable to those of [1 1 1] rods. The saturated magnetostriction measured in a parallel magnetic field is lambda(parallel to) = 1124 x 10(-6) under 0 MPa and increases to 1760 x 10(-6) under a compressive stress of 25 MPa. The pseudolinear variation of the magnetostriction with the internal magnetic field Delta lambda(parallel to)/mu(0)Delta H-int reaches 640 x 10(-6)/0.04 T under 9.9 Mfa. The texture and the good magnetostrictive properties are reproducible.