Spontaneous magnetostriction of Y₂Fe₁₆Al compound

The structure and magnetic properties of Y₂Fe₁₆Al compound have been investigated by means of x-ray diffraction and magnetization measurements. The Y₂Fe Fe₁₆Al compound has a hexagonal Th_2Ni_17-type structure. Negative thermal expansion was found in Y₂Fe₁₆Al compound in the temperature range from 332 to 438K by x-ray dilatometry. The coefficient of the average thermal expansion is \bar\alpha =-3.4\times 10^-5K^-1. The spontaneous magnetostrictive deformations from 293 to 427K have been calculated based on 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 \omega _\rm S decreases from 5.4\times 10^-3to near zero with temperature increasing from 293 to 427K, the spontaneous linear magnetostrictive deformation \lambda_\rm c along the c axis is much larger than the spontaneous linear magnetostrictive deformation \lambda _\rm a in basal-plane in the same temperature range except near 427K.