Experimental details Porous Ba minus xSrxTiO

During the sintering, the graphite burned out and resulted CO2 was eliminated, while the places occupied initially by graphite platelets became internal micro/macropores distributed in the volume of the ceramic body. After sintering the green compacts, shrinked disc-shaped dense of porous BST samples with various porosities were obtained. To remove the possible stresses due to the sintering and to allow the full reoxidation, the ceramic samples were heated at 1100 °C/36 h and slowly cooled down to room temperature.