Transport properties in bulk nanocrystalline Sm-doped ceria with doping content between 2 and 30Â at.%

► We densified Sm-doped ceria samples by High-Pressure Field Assisted Sintering. ► At 600 °C in 5 min grain size below 20 nm and full density was obtained. ► By impedance spectroscopy the samples showed single semicircle due to grain boundary. ► With brick layer model we compared our results to microcrystalline materials. ► Reduction of grain size does not produce differences in grain boundary conductivity.