Spontaneous Magnetostriction of R2Fe13.6Si3.4 (R: U, Lu).

Abstract The thermal expansion of U 2 Fe 13.6 Si 3.4 and Lu 2 Fe 13.6 Si 3.4 has been measured by X-ray powder diffraction. Both compounds exhibit a large spontaneous magnetostriction. In the ground state, the volume effect 11.2 × 10 −3 in U 2 Fe 13.6 Si 3.4 consists of almost equal contributions from the Fe–Fe and U–Fe exchange interactions (6 × 10 −3 and 5 × 10 −3 , respectively). In Lu 2 Fe 13.6 Si 3.4 , the volume effect is 8.9 × 10 −3 .