Some novel electromagnetic effects in the conductivity of molten organic salts

Abstract

Considerable frequency dispersion of electrical conductivity has been ob­served in the liquid crystal phases of organic ionic melts, depending on their molecular structure and domain size. Dispersion began to be detectable above about 10000 Hz for sodium isovalerate (in which there are large domains), and above about 2000 Hz for sodium n -butyrate (domains about 0.1 mm across). Neither molten salt showed dispersion in a middle range of frequencies (between 1000 Hz and 100Hz). Previous researches had shown a marked diamagnetic anomaly of molten organic salts when these are cooled through their mesophases, while applying static magnetic fields. The kind of response observed can be attributed to interaction between ‘liquid crystal’ domains and the applied fields. A related effect has now been observed when a static magnetic field (approx. 10kG) was applied in the course of the above measurements of electrical conductivities. With sodium isovalerate melts, a magnetic field applied perpendicular to the electric field reduced by a factor of two the drop in electrical conductivity when the isotropic melt passed into its mesophase. No effect (≯ 2%) was detected with sodium n -butyrate under the same conditions.