I have a Linear research Inc. model LR-700 AC resistance bridge which is the benchmark for resistance measurements. However, for some reason, the metallic thin film sample that I am currently measuring is showing a negative resistance.
Some more detail, even though I don't believe the sample has any inductance, the LR-700 measures about -400 Kohm reactance (mutual inductance). This -400kohm reactance is measured in the resistance range of 2 Mohm. I believe that the resistance range is coupled for measuring both the resistance and the reactance. Hence, the lowest measurable resistance in the 2Mohm range is 10Kohm. I observe that the resistance value goes negative after reaching this value of 10Kohm, which might mean that the resistance value is out-of-range, but since the reactance value is still in the 2Mohm range, the range remains at 2Mohm. I am unable to find any information about the negative resistance measured by a LR-700 AC resistance bridge. I am wondering if anyone has also encountered a similar problem or figured out how to interpret a negative resistance measured. I would be immensely grateful if someone can help me understand this. Thank you.