Electrical properties of BiSrCaCuO (2223) films

The mechanisms of electrical conductivity of BiSrCaCuO (2223) films in a wide range of structural states are investigated. In the amorphous state (ρ= 103– 1010 Ω · cm), the films exhibit jump condutivity with a varying length of jumps. As the crystalline structure starts being formed (ρ= 10–103 Ω · cm), the electric properties of the films resemble the properties of granular films with an exponential dependence of resistivity on the separation between granules with the metal-type conductivity up to the transition to a state with metal conductivity (ρ ≃10−2 Ω · cm). In the vicinity of the insulator–metal transition, the films have power dependences of electrical conductivity on temperature with exponents 1/2 and 1/3. A transition to metal-type conductivity is of percolation type and takes place for the metal-phase concentration cm≃ 0.2.