关键词: Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound, spontaneous magnetostriction, negative thermal expansion

Abstract: The structural and magnetic properties of Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound have been investigated by means of x-ray diffraction and magnetization measurements. The Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound has a hexagonal Th$_{2}$Ni$_{17}$-type structure. Negative thermal expansion is found in the Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound at the temperatures ranging from 245 to 344K by x-ray dilatometry. The coefficient of the average thermal expansion is $\overline{\alpha}=-1.1\times 10^{-4}$K$^{-1}$. 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.

Key words: Dy$_{2}$AlFe$_{13}$Mn$_{3}$ compound, spontaneous magnetostriction, negative thermal expansion