Electric Field Enhancement and Conduction Mechanisms in Ni/BaTiO3 Percolative Composites

Ni-BaTiO3 composites have revealed to be an optimal system to prepare materials with very high permittivity. In this sense, an exhaustive characterization of these materials under strong electric fields is mandatory. In this article, leakage currents of such composites, with nickel contents very close to the percolation threshold (fc = 0.31), have been measured, analyzed and identified to present Schottky and tunneling conductivity mechanisms, for moderate and strong applied field regimes, respectively. According to the Schottky model, internal fields resulted to be largely enhanced (enhancement factors as large as 104) with respect to the monolithic BaTiO3 ceramics.