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

Chimi, Yasuhiro; Ishikawa, Norito; Iwase, Akihiro*

Materials Research Society Symposium Proceedings, Vol.792, p.379 - 384, 2004/00

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 (300-600 10 K with several kinds of energetic (100-200 MeV) heavy ions. The resistivity of the specimen is measured in-situ at 7 K during irradiation. After irradiation, annealing behavior of the resistivity is observed up to 35 K. The temperature dependence of the resistivity during annealing shows an abrupt increase around 20 K, implying re-crystallization of irradiation-induced amorphous region. Since amorphous bismuth also shows a superconducting transition below 6 K, high-density electronic excitation due to energetic heavy-ion irradiation may induce columnar region of superconducting amorphous bismuth in normal crystalline bismuth. We are trying to detect the superconducting transition as a result of irradiation-induced amorphization.