  We report $^{75}$As-NMR results for CrAs under pressure, which shows
superconductivity adjoining a helimagnetically ordered state. We successfully
evaluated the Knight shift from the spectrum, which is strongly affected by the
quadrupole interaction. The Knight shift shows the remarkable feature that the
uniform spin susceptibility increases toward low temperatures in the
paramagnetic state. This is in sharp contrast to CrAs at ambient pressure, and
also to cuprates and Fe pnictides, where antiferromagnetic correlations are
dominant. Superconductivity emerges in CrAs under unique magnetic correlations,
which probably originate in the three-dimensional zigzag structure of its
nonsymmorphic symmetry.
