Magnetic Phase Transitions in Intermetallic GdNi$\text{}_{5-x}$Sn$\text{}_{1+x}$ and TbNi$\text{}_{5-x}$Sn$\text{}_{1+x}$ Compounds

Magnetization measurements were performed for intermetallic compounds GdNi$\text{}_{5-x}$Sn$\text{}_{1+x}$ and TbNi$\text{}_{5-x}$Sn$\text{}_{1+x}$ in the temperature range from 4.5 K to 280 K and in magnetic field up to 50 kOe. Complex magnetic phase diagram was revealed for both compounds. The results are discussed assuming three-sublattice magnetic structure and partial disordering of the structure.