Browsing by Author "de Castro, MJ"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Ionic conductivity and stored energy in gamma-irradiated NaF
    (1998) Mariani, DF; Ibarra, A; de Castro, MJ
    Gamma irradiation reduces the ionic conductivity of NaF single crystals due to the decrease of the extrinsic cation-vacancy concentration. Irradiation also makes the binding energy of the impurity-cation-vacancy dipole higher than that for unirradiated samples. The thermal recovery of these effects takes place between 270 and 600 degrees C, which is the range in which the main stored-energy release peak occurs. The energy released below 600 degrees C, when the irradiated sample is heated, is 1.9 x 10(20) eV g(-1). It is proposed that these processes are related to radiation-induced divacancies, that behave as traps for the impurity-cation-vacancy dipoles.
  • No Thumbnail Available
    Item
    Ionizing radiation effects on the ionic conductivity of NaCl
    (1998) Mariani, DF; Gonzalez, F; de Castro, MJ
    Gamma irradiation or plastic deformation reduces the ionic conductivity of NaCl single crystals because of the decrease of the extrinsic cation vacancy concentration. Two steps in the thermal recovery of this vacancy concentration have been observed to occur between 200 degrees C and 620 degrees C in pulsed thermal annealing experiments. The ascription of these effects to dislocations and divacancy clusters acting as traps for the impurity-cation vacancy dipoles is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.