4. Magnetic properties

After presenting the effects of partial substitution of iron by gallium on the crystallographic parameters of equilibrium alloys Sm ₂ Fe _17–x Ga _x and non-equilibrium precursors SmFe _9–y Ga _y , we follow the evolution of the intrinsic magnetic properties (Curie temperature, hyperfine parameters) of these compounds. We attempt to correlate these properties with structural modifications induced by substitution, for both classes of compounds.