Magnetization of Pd_1-xNi_x near quantum criticality

Ni-doped Pd exhibits a paramagnetic to ferromagnetic quantum phase transition at x_c ≈ 2.5%. We report the magnetic field dependence of the magnetization of Pd_1-xNi_x for x = 2.59% at various temperatures. The nonlinear magnetization is well described by a conventional mean-field behavior at high temperatures and high magnetic fields. At low fields and low temperatures the magnetic field dependence deviates markedly from mean-field behavior suggesting a more complex magnetic state. Our study questions recent claims that Pd_1-xNi_x exhibits a ferromagnetic quantum criticality akin a pure itinerant ferromagnet.