Thus, an explanation for the difference in the low-pressure behavior of La0.9Ba0.1F2.9 and Ba0.6La0.4F2.4 could be as follows. For Ba0.6La0.4F2.4 many voids or cracks could be found which are at least partially oriented perpendicular to the axis of force, which will have opened up when the applied stack pressure dropped below a certain threshold value. Since for La0.9Ba0.1F2.9, a much smaller number of those cracks were found, such a loss of conductivity due to crack formation is not to be expected, matching the observation from the impedance measurements.