  We report low-temperature and high-pressure measurements of the electrical
resistivity \rho(T) of the antiferromagnetic compound NiS_2 in its
high-pressure metallic state. The form of \rho(T) suggests that metallic
antiferromagnetism in NiS_2 is quenched at a critical pressure p_c=76+-5 kbar.
Near p_c the temperature variation of \rho(T) is similar to that observed in
NiS_{2-x}Se_x near the critical composition x=1 where the Neel temperature
vanishes at ambient pressure. In both cases \rho(T) varies approximately as
T^{1.5} over a wide range below 100 K. However, on closer analysis the
resistivity exponent in NiS_2 exhibits an undulating variation with temperature
not seen in NiSSe (x=1). This difference in behaviour may be due to the effects
of spin-fluctuation scattering of charge carriers on cold and hot spots of the
Fermi surface in the presence of quenched disorder, which is higher in NiSSe
than in stoichiometric NiS_2.
