Impedance and dielectric properties of Bi2Sn2-хFeхO7 stannates

Bismuth stagnnates Bi2Sn2-хFeхO7, х = 0,1; 0,2 which reveal the properties of multiferroics, are investigated. The mechanism of interaction between dielectric and electronic subsystems is studied, based on measurements of electrical resistance at alternating current, impedance, capacitance and dielectric loss tangent in the temperature range 100-600 K at frequencies 102-106 Hz. From a comparison of the dielectric permittivity and the reactive component of impedance, the paramagnetic contribution of electrons to the dynamic magnetic susceptibility was established. Impedance jumps on temperature were detected as a result of changes in structural characteristics. The temperature dependences of the permittivity are described in the Debye model. An activation character of the relaxation time and two relaxation channels were found. The activation energy of electrons in the migratory polarization is calculated.