Tunneling Magnetodielectric Effect in Co–Al<sub>2</sub>O<sub>3</sub> Granular Films

Giant Hall effect in superparamagnetic granular films

A comprehensive review of the giant Hall effect (GHE) is presented, with emphasis on novel experimental data obtained in Ni–SiO2 and Co–SiO2 films prepared by co-sputtering. GHE is observed close to and on both sides of the metal–insulator transition. From the point of view of microscopic conduction mechanisms, this means a crossover from metallic conductivity with weak localization to tunnelin...

Negative magnetodielectric effect in CaCu3Ti4O12

Tunneling into granular Pb films in the superconducting and insulating regimes.

Competing tunneling and capacitive paths in Co-ZrO2 granular thin films

The ac electrical response is studied in thin films composed of well-defined nanometric Co particles embedded in an insulating ZrO2 matrix which tends to coat them, preventing the formation of aggregates. In the dielectric regime, ac transport originates from the competition between interparticle capacitive Cp and tunneling Rt channels, the latter being thermally assisted. This competition yiel...

Tunneling density of states of granular metals

We investigate the effect of Coulomb interactions on the tunneling density of states (DOS) of granular metallic systems at the onset of Coulomb blockade regime in two and three dimensions sd=2,3d. Using the renormalization group technique we derive the analytical expressions for the DOS as a function of temperature T and energy «. We show that samples with the bare intergranular tunneling condu...