  We report a study of the low-temperature high-pressure phase diagram of the
intermetallic compound PrCu$_2$, by means of molecular-field calculations and
$^{63,65}$Cu nuclear-quadrupole-resonance (NQR) measurements under pressure.
The pressure-induced magnetically-ordered phase can be accounted for by
considering the influence of the crystal electric field on the $4f$ electron
orbitals of the Pr$^{3+}$ ions and by introducing a pressure-dependent exchange
interaction between the corresponding local magnetic moments. Our experimental
data suggest that the order in the induced antiferromagnetic phase is
incommensurate. The role of magnetic fluctuations both at high and low
pressures is also discussed.
