Effects of high-energy ion irradiation in bismuth thin films at low temperature

We have studied high-energy ion irradiation effects in bismuth by measuring the electrical resistivity at low temperature in relation to its structural change. Bismuth thin films (330-520 Angstrom thick) are irradiated below similar to10 K with energetic (150-200-MeV) heavy ions. The resistivity of the specimen is measured in situ below similar to7.2 K during the irradiation. After the irradiation, annealing behavior of the resistivity is observed up to similar to30 K. The temperature dependence of the resistivity during annealing shows an abrupt increase around 20 K, implying re-crystallization of irradiation-induced amorphous regions. We have tried to detect a superconducting transition which may take place as a result of irradiation-induced amorphization. In the range of the measuring temperature down to similar to4.9 K, resistivity decrease clue to superconducting transition has not been observed in the temperature dependence of the resistivity after 200-MeV (197) Au ion irradiation up to a fluence of 3.1x10(12) CM-2.