Metal-semiconductor transition and Kondo question at low temperature for dilute Mn doping Na0.7Co1-xMnxO2 systems

We present the results of low temperature transport behavior and magnetic properties for dilute Mn-doped Na0.7Co1-xMnxO2 system with x = 0, 0.03, 0.07, 0.1. The results show that the electrical transport properties are very sensitive to Mn doping at low temperatures and a novel resistivity minimum is found with a characteristic of metal-semiconductor transition (<50 K). These can be understood by within the theory of Kondo scattering and electron-electron interaction enhanced by disorder upon magnetic Mn doping. The data of doped samples are well fitted by the two scattering mechanisms in a wide temperature range of 2-100 K. The results show that Na0.7Co1-xMnxO2 is a kind of typical Kondo-like oxide as the conventional dilute alloys and strong correlation system