I've deposited REFeO3 thin film, with RE=La, Pr, Nd and Sm. I've performed 4-probes measurements, in range 400-600°C (intrinsic domain). As expected, smaller RE cation gives higher resistivity, but when I linearize the curve by Arrhenius Plot, I obtain decrease of activation energy with smaller RE.
It should suggest easier conduction mechanisms with smaller RE, but a higher resistivity. I have no explanation for that, and I need suggestion!