Abstract Current measurements, as functions of voltage ( I – V curves), at different temperatures were carried out in SrTiO 3 +Nb/Pb(Zr 0.52 Ti 0.48 )O 3 /Ag capacitor structures grown on (100) SrTiO 3 Nb‐doped substrates by using a technique of high‐oxygen pressure on axis sputtering. Crystalline quality and structure were measured by X‐ray diffractometry (XRD). Surface roughness and morphology were studied by atomic force microscopy (AFM). Ferroelectric characterization was conducted by P – E hysteresis loops on different capacitors with electrode areas of 5.0×10 –4 and 6.5×10 –3 cm 2 . Conductance measurements revealed a hopping mechanism of conduction through 2 or 3 localized states in the range of temperatures between 130 K and 40 K. On the other hand, in the temperature range between 385 K and 180 K, our results fit very well with the variable range hopping (VRH) model. The measurements of current as a function of voltage on SrTiO 3 +Nb/PZT/Ag structures showed typical electronic tunneling behavior. The process of electronic tunneling through capacitive structures can be interpreted as a transition from hopping mechanisms via N localized states to variable range hopping, when temperature is increased. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)