Magnetoresistance in Cu Ferrite System

Abstract

Polycrystalline Cu_1-xFe_2+xO4(x=0, 0.25, 0.50, 0.75, 0.90) samples with spinel structure were prepared by the conventional ceramic process. The samples were sintered in N2at 1100-1400°C for 2 hours. The resistivity of all the samples is in 10^-2 10Ωcm, which is low as a ferrite. This originates in the hopping conduction between Cu¹⁺ and Cue²⁺, and between Fe²⁺ and Fe³⁺ in all the samples. MR ratio at room temperature in Cu_0.50Fe_2.50O₄ became maximum 10.4%. This value is large twice compared with that of Fe₃O₄ reported before. The curves of MR and magnetization of Cu_0.05Fe_2.50O₄ have correlation, in which resistance decreases as magnetization increases. The MR effect is coused by magnetic scattering.