The Relation between Electrical Conductivity Mechanisms and Magnetic After-Effects in Single Crystal Magnetite

抄録

Measurements of electric conductivity and magnetic after-effect have been performed on single crystalline magnetite in order to obtain more information on the conductivity mechanisms below the Verwey temperature T_v≈124 K. Depending on the stoichiometry of the material, two or three temperature ranges were detected which are characterized by different magnetic relaxation processes and within which the conductivity follows Mott’s T^1⁄4-law as derived for the case of multi-range electron hopping. By combined measurements of the electrical conductivity and of the magnetic after-effects the activation energies for intra-atomic electronic excitations and inter-atomic hopping transitions of electrons were determined.