Magnetostriction of RFe₁₁Ti and RFe₁₀Cr₂

The magnetostriction of polycrystal RFe₁₁Ti (R=Nd, Sm, Gd, Tb, Dy, Ho, Er and Y) and RFe₁₀Cr₂(R=Tb and Dy) compounds with ThMn₁₂-typestructure have been investigated at 77K and room temperature in magnetic fields up to 20kOe. The values ofmagnetastriction λ_t = λ_|| - λ_⊥ in H=20kOe at 300K are 180 x10^-6 for TbFe₁₁Ti and 106x10^-6 for Tb₁₀Cr₂. The magnetostrictions for compounds with R=Nd, Sm, Dy, Ho and Er are very small. The signs of λ_t for all these compounds are in agreement with that predicted by the singleion crystal field theory. All studied samples show a volume magnetostriction feature. Their forced magnetostrictions Δω/ΔH have a value which is close to that of YFe₁₁Ti, 27 x 10^-10/Oe. It reveals that the Fe sublattice is responsible for the volumc magnetostriction.