Electrical conductivity measurements of some layered magnetic structures

The electrical conductivity for temperatures up to 416 K has been measured in several of the alkylammonium tetrahalidemetallate and the alkanediammonium tetrahalidemetallates where the halides were bromine and chlorine and the metal was copper or, in one case, cadmium. These salts are all good magnetic insulators at low temperature but behave as ionic, probably protonic, semiconductors as the temperature is increased. Room temperature conductivity for these samples is of order 10−12 Ω−1 cm−1 and varies as much as ten orders of magnitude over the measured temperature range. The possibility that the changes in activation energy are related to known structural phase transitions is discussed.