ALPHA-IRRADIATION INDUCED CHANGES IN FLUCTUATION-CONDUCTIVITY IN (BI,PB)-2223 SUPERCONDUCTORS

We have irradiated (Bi,Pb)-2223 superconductors by 40 meV alpha-partic les. The irradiation induces changes in resistivity as we increase the dose of irradiation. The various doses change the resistivity as a re sult of which the fluctuation induced conductivity also changes. We ha ve analysed the experimental observations in the framework of Aslamazo v-Larkin, Lawrence-Doniach and Maki-Thompson theory. We have extracted coherence lengths, dimensional crossover temperature and Josephson in terlayer coupling strength. The role of disorders induced by irradiati on has been discussed in this respect. The change in the fluctuation-c onductivity is discussed in the light of the coherence length and the critical magnetic field H-c. (C) 1997 Elsevier Science Ltd.