Previous results for samples prepar

Previous results for samples prepared by conventional sintering in our group are recalled on Fig. 13 [1]. For these samples, we obtained an evolution trend similar to Fig. 2, i.e. the total conductivity of the sample limited at low temperatures by the grain boundary, and at high temperatures by the bulk, but the intersection of the two curves was observed at higher temperature, near 530 °C, instead of 200 °C, as it was shown on Fig. 2.