Quantum corrections to the conductivity in a perovskite oxide: A low-temperature study of ${\mathrm{LaNi}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Co}}_{\mathit{x}}$${\mathrm{O}}_3$ (0≤x≤0.75)

In this paper we propose to study the evolution of the quantum corrections to the conductivity in an oxide system as we approach the metal-insulator (M-I) transition from the metallic side. We report here the measurement of the low-temperature (0.1 K<T0.65), m takes on large values and σ(0)=0. We explain the temperature dependence of σ(T), for T<2 K, on the metallic side (x≤0.4), as arising predominantly from electron-electron interactions, taking into account the diffusion-channel contribution (which gives m=0.5) as well as the Cooper-channel contribution. In this regime, the correction to conductivity, δσ(T), is a small fraction of σ(T). However, as the M-I transition is approached (x→${\mathit{x}}_{\mathit{c}}$), δσ(T) starts to dominate σ(T) and the above theories fail to explain the observed σ(T).