Structural Modifications of Crystalline and Amorphous Ni sub 3 B Irradiated With High-Energy Heavy Ions

Crystalline and amorphous Ni sub 3 B ribbons have been irradiated at low temperature with GeV heavy ions in order to study the structural modifications induced in metallic alloys by ion electronic energy loss. The atomic rearrangements produced by irradiation were characterized via in situ electrical resistance measurements and room-temperature X-ray and electron diffraction. Amorphous Ni sub 3 B behaves as the other amorphous alloys already investigated: creation of disorder with a cross section increasing with the ion electronic stopping power, followed by an anisotropic growth of the sample dimensions. Crystalline Ni sub 3 B shows a new and very interesting behaviour: a huge electrical resistivity increase above an electronic energy loss threshold attributed to amorphization of the irradiated alloy.