Low-temperature resistivity minimum in dilute Mn-doping Na_(0.7)Co_(1-x)Mn_xO_2: A Kondo-like oxide with strong disorder characteristics

摘要

We present the results of low-temperature transport behavior and magnetic properties for dilute Mn-doped Na_(0.7)Co_(1-x)Mn_xO_2 system with x=0, 0.03, 0.07, 0.1. The results show that the properties are very sensitive to Mn doping at low temperatures. A unique resistivity minimum is found with a characteristic of metallic-semiconductor transition ( < 50 K) for all the doped samples. Combining with the resistivity data in applied field, it can be understood within the theory of Kondo scattering induced by magnetic impurities and electron-electron (e-e) interaction enhanced by disorder. The best fitting was made in the framework of the two scattering mechanisms in a wide temperature range of 2-100 K. The results prove that the layer Na_(0.7)Co_(1-x)Mn_xO_2, a kind of typical Kondo-like oxide like the dilute convention alloys, is a strong disorder system in which exists enhanced e-e interaction, which reflects a typical characteristic of strong correlation systems.