Crystalline Ni3B samples have been irradiated
with GeV heavy ions (from 16O to 238U) at
low temperature in order to study the damage induced in this
compound by ion electronic energy loss. Electrical resistance
measurements were performed in situ during irradiation and
during annealing. Subsequent X-ray diffraction
data and transmission electron microscopy observations reveal
a change of the radiation damage process as a function of the
electronic stopping power (dE/dx)e. At low (dE/dx)e isolated
defects are created, while at high (dE/dx)e irradiation generates
continuous amorphous tracks. Amorphous inclusions (discontinuous
tracks) are most likely formed in the intermediate (dE/dx)e range.
The amorphous phase induced by swift heavy ion irradiation, different
from that formed by quenching techniques, is unstable at room
temperature over a period of a few months.