ac Conductivity of mixed spinel NiAl0.7Cr0.7Fe0.6O4

摘要

ac Conductivity measurements are carried out across the metal to insulator transition in NiAl0.7Cr0.7Fe0.6O4. The low frequency data is analyzed using Summer???eld scaling theory for hopping conductivity. The exponent of the scaling behavior has signi???cantly different values in the conducting and insulating regimes. The hopping frequency and the zero frequency conductivity are found to increase with temperature, slowly in the metallic regime and rapidly in the insulating regime.