Magnetic ordering in the hyperfine enhanced nuclear ferromagnetic PrNi5 was
investigation in external magnetic fields up to 72 mT at temperatures from
below the ordering temperature up to about 20 mK. An anisotropy of the mag
netization and ac susceptibility was observed for two single crystalline sa
mples having a or c crystallographic axis parallel to rite external field.
The results show that the nuclear magnetic moments of PI are ordered in the
basal plane of the hexagonal crystal structure of PrNi5.