Spontaneous magnetostriction of the HeDy2AIFe8Mn8 compound

摘要

The thermal expansion behaviors of the unit-cell volume of the Dy2AIFe8Mn8 compound from 104 to 643K and its spontaneous magnetostrictions are investigated by means of x-ray dilatometry and magnetization measurements. The results show that there exists a negative thermal expansion in the temperature range 150-230K. The average coefficient of the thermal expansion is α=-5.36×10-5K-1. The spontaneous magnetostrictive deformations from 104 to 235K have been calculated. The results show that the spontaneous volume magnetostrictive deformation ωs increases from 4.4×10-3 at 104K to 7.1×10-3 at 150K with the temperature increasing, and then decreases with the temperature increasing further. The spontaneous linear magnetostrictive deformation λc along the c-axis decreases with the temperature increasing while deformation in the basal-plane λa increases from 0.9×10-3 at 104K to 2.4×10-3 at 145K with the temperature increasing and then decreases with the temperature increasing further.