X-ray investigation and discussion of the magnetostriction of Gd₃T (T = Ni, Rh, Ir_x) single crystals

The variations of the lattice parameters of Gd₃T (T = Ni, Rh, Ir_x) single crystals with temperature were measured in the range 10-300 K. The compounds with Ni and Rh crystallize in the orthorhombic space group Pnma, but the compound with Ir crystallizes as Gd₅Ir₂ in the monoclinic space group A2/a. The three compounds exhibit an anomalous anisotropic spontaneous magnetostriction below the magnetic ordering temperature.