Spontaneous magnetostriction of Ce₂Fe₁₇

X-ray diffraction study of the thermal expansion of Ce₂Fe₁₇ showed large positive spontaneous linear (λ_a and λ_c) and volume (ω-s$/) magnetostrictions resulting in the Invar effect in a wide temperature range below ≈250 K. At 10 K, λ_a = 3.0×10^-3, λ_c = 3.5×10^-3, and ω-s$/ = 9.5×10^-3. Transition from the ferro- to the antiferromagnetic state reduces the magnetostrictions, slightly for λ_c and strongly for λ_a, leading to a more pronounced anisotropy of the spontaneous magnetostriction.