Magnetic properties of binary alloys Ni_1-xMo_x and Ni_1-yCu_y close to critical concentrations

The search for the ferromagnetic quantum critical point (FM QCP) has always been a captivating research topic in the scientific community. In pursuit of this goal, we introduced nonmagnetic transition metals to alloy with elemental nickel, and studied the magnetic properties of nickel binary alloys Ni_1-xMo_x and Ni_1-yCu_y as a function of x and y up to the critical concentrations x_cr and y_cr at which the FM transition disappears. T_c-x(y) phase diagrams were constructed via the Arrott–Noakes scaling of magnetization data. An enhanced Sommerfeld coefficient (the value of C/T as T→ 0) is observed near x_cr and y_cr, manifesting the effect of quantum fluctuations. However, the spin glass behavior is identified through the ac magnetic susceptibility measurements. This observation rules out the possibility of the existence of the FM QCP in both systems.