Effect of Ti doping on the electrical transport and magnetic properties of layered compound Na0.8CoO2

Effect of Ti doping on the electrical transport and magnetic properties of layered Na0.8Co1−xTixO2 compounds has been investigated. The lattice parameters a and c increase with x. A minor amount of Ti doping results in a metal-insulator transition at low temperatures. For samples with x>0.03, the variable-range hopping process dominates the transport behavior above a certain temperature. The temperature dependence of magnetization of all the samples is found to obey the Curie-Weiss law. The mechanism of the doping effect is discussed.