Magnetic properties of RNi5−xCux intermetallics

The magnetic properties have been studied for the series of RNi_5−xCu_x intermetallics with R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu; x  ?2.5. Compositional dependences of magnetic susceptibility for the Pauli paramagnets (R=Y, La, Ce, Lu) and the Curie temperature for ferromagnets (R=Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm) have maximum at x=0.2–0.4$x=0.2–0.4$ and 1, respectively. The substitution of Cu for Ni is accompanied by decreasing spontaneous magnetic moment and increasing coercive force of all ferromagnetic RNi_5−xCu_x but GdNi_5−xCu_x. These results are explained in the frame of band magnetism, random local crystal field, and domain wall pinning theories.