YBa_2Cu_3O_<7-δ>酸化物高温超伝導薄膜に対する放射線照射効果

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Effects of radiation of 28 MeV electrons, fast neutrons, 0.5-2.5 MeV ions such as H^+, He^+, O^+, Ar^+ and Ni^<2+> on YBa_2Cu_3O_<7-δ> thin films were investigated. The normal resistivity and c-axis lattice constant increased with fluence. Below a threshold fluence for each irradiation the critical temperature(T_c) was constant, while above this fluence T_c decreased with fluence. On the other hand, the transport critical current density(J_c) increased in the low fluence range with a maximum value of 4-30% in enhancement ratio at an optimum fluence, and decreased in the high fluence range. The decrease in J_c was supposed to come from the degradation of grain boundaries as well as intragrains. The threshold fluence φt decreased with the mass A of incident ions in the relation, φt/cm^<-2>=10^<17>(A/amu)^<-2.5>. For each case of irradiation the threshold fluence and the optimum fluence gave 10^<-2> and 10^<-4>-10^<-5> dpa, respectively, and at the latter fluence cascade damage regions begin to overlap.
社団法人日本セラミックス協会の論文
1996-10-01