Electric Conduction of Ferrites containing Fe²⁺-ions

The D.C. electric conductivity was measured between 100°K and 300°K for the ferrite solid solution (MeFe 2 O 4 ) 1- y Fe 3 O 4 ) y , where Me=Mn, Ni, Mn-Ni or Zn. Above 120°K the specific conductivity of each specimen depends on temperature as σ= A ·exp (- ε / k T )/ T . The activation energy ε is (5∼8)×10 -2 eV. A depends on the concentration, y , of Fe 3 O 4 as A =(6.5±2.5)×10 4 ( y /1- y ) degree/Ωcm. The analysis of these experimental expressions shows that the dependence of the mobility on temperature for each specimen can be fitted by the expression, µ=µ 0 ·exp (- ε / k T )/ T and the dependence on the Fe 2+ -ion concentration, y , by µ 0 =(3.0±1.2)×10 1 (1/1- y ) degree (cm 2 /volt sec). µ 0 is independent of the kind and distribution of Me 2+ -ions.