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

An ion-radical salt, (ESBN)₂ClO₄, obtained from the electrochemical crystallization of an organic donor radical, ESBN, exhibited giant negative magnetoresistance (-70% at 2 K in 9 T) in spite of the absence of metal ions. Furthermore, it was found that the conductivity of (ESBN)₂ClO₄ was characterized by a distinct nonlinear temperature dependence and a nonlinear power law of I∝Vⁿ $(n=12)$. We speculated that such correlated spin-dependent electron transportation is derived from the charge-ordered electronic structure and the strong intramolecular ferromagnetic coupling between π-conduction electrons and π-localized spins in the ``spin-polarized donor.''