Molecule-based system with coexisting conductivity and magnetism and without magnetic inorganic ions

Abstract

An ion-radical salt, ${(\text{ESBN})}_{2}{\text{ClO}}_{4}$, obtained from the electrochemical crystallization of an organic donor radical, ESBN, exhibited giant negative magnetoresistance ($\ensuremath{-}70%$ at 2 K in 9 T) in spite of the absence of metal ions. Furthermore, it was found that the conductivity of ${(\text{ESBN})}_{2}{\text{ClO}}_{4}$ was characterized by a distinct nonlinear temperature dependence and a nonlinear power law of $I\ensuremath{\propto}{V}^{n}$ $(n=12)$. We speculated that such correlated spin-dependent electron transportation is derived from the charge-ordered electronic structure and the strong intramolecular ferromagnetic coupling between $\ensuremath{\pi}$-conduction electrons and $\ensuremath{\pi}$-localized spins in the ``spin-polarized donor.''