Impedance spectroscopy of single grain junction in Nb-doped SrTiO3

To our knowledge, a micro-electrode method was firstly used to measure the impedance of single grain to grain junction of Nb-doped SrTiO3. It was found that the complex impedance plot composed of three semi-arcs. It was assumed that the three arcs were represented the grain, the grain boundary, and the compensated layer between grain and grain boundary, respectively. It was noticeable that the simulated result based on the equivalent electrical circuit was very well. fitted with the experimental value. Although Nb-doped SrTiO3 was sintered in air, the single grain to grain junction could be represented as an equivalent n-c-i-c-n model.