EPR investigation of the electronic states in β′-type [Pd(dmit)2]2 compounds (where dmit is 2-thioxo-1,3-dithiole-4,5-dithiolate)

Magnetic investigations of organic conductors, β′-type [Pd(dmit)2]2, have been performed by Electron Paramagnetic Resonance (EPR) measurements. We found that most of them except one compound underwent antiferromagnetic transitions. Although they are isostructural with little differences in lattice parameters, their spin–spin correlations and antiferromagnetic transition temperatures show strong counter ion dependence. The EPR g-values of Pd(dmit)2 cannot be explained within the framework of isolated radical description which is a good approximation for conventional organic conductors. The electronic structures of a series of molecular conductors based on Pd(dmit)2 at ambient pressure are discussed from microscopic points of view.