Spontaneous magnetostriction of Dy₂ AlFe₁₃ Mn₃ compound

The structural and magnetic properties of Dy_2AlFe_13Mn_3 compound have been investigated by means of x-ray diffraction and magnetization measurements. The Dy_2AlFe_13Mn_3 compound has a hexagonal Th_2Ni_17-type structure. Negative thermal expansion is found in the Dy_2AlFe_13Mn_3 compound at the temperatures ranging from 245 to 344K by x-ray dilatometry. The coefficient of the average thermal expansion is \overline\alpha=-1.1\times 10^-4K^-1. The spontaneous magnetostrictive deformations in the 105--360K temperature range have been calculated by means of the differences between the experimental values of the lattice parameters and the corresponding values extrapolated from the paramagnetic range. The result shows that the spontaneous volume magnetostrictive deformation \textit\omega _\rm s increases from 7.0\times 10^-3 at 105K to 9.1\times 10^-3 at 245K, and then decreases with the temperature increasing. The spontaneous linear magnetostrictive deformation \lambda_c along the c axis decreases as temperature increases. The spontaneous linear magnetostrictive deformation \lambda_a in basal-plane increases from 0.8\times 10^-3 at 105K to 3.4\times 10^-3 at 270K, and then decreases with the temperature increasing further.