Magnetic impurity effect in Pd-doped Ni₃Al

Isothermal magnetization curves of Ni_77-xAl₂₃Pd _x (0<or=x<or=3) intermetallic compound have been measured in the temperature range between 4.5 K and 110 K. The temperature dependence of spontaneous magnetization, M_s(T), has been analysed according to the self-consistent renormalization theory of spin fluctuations. The qualitative agreement between the experimental result and the theoretical one is satisfactory. The value of Curie temperature, T_C as well as M _s(0) does not vary significantly with the Ni concentration, though it varies remarkably in the Ni_75+xAl_25-x system. Pd impurity atoms occupy the Ni site and the Ni atoms expelled by the Pd atoms reside on the Al site. The expelled Ni atoms give the same magnetic effect as the excess Ni atoms in the off-stoichiometric binary compound. The values of T_C and M_s(0) depend on the number of Ni atoms on the Al site, as well as on the Ni site, and the former is predominant.