Spin fluctuations on the verge of a ferromagnetic quantum phase transition in Ni3Al1-xGax

Ni3Al1-xGax alloys are investigated by the measurements of isothermal magnetization, temperature variations of susceptibilities, and specific heats. Ga doping depresses the ferromagnetic transition temperature (T-C) continuously below the critical point x = 0.34. Near the critical region (x approximate to 0.34), the quantum critical scaling behaviors manifest themselves as the initial susceptibility chi(-1)(T) alpha T-4/3, T-C(4/3) alpha (x - x(c)), and specific heat divided by temperature as C/T alpha lnT at low temperatures. Furthermore, a novel spin-fluctuation spectrum was discovered in the samples near the quantum critical point, confirming the quantum critical point in this system. The magnetic properties in this system are understood almost in terms of the self-consistent renormalization and Takahashi's theory of spin fluctuations.