材料期刊网

An unusual thermoelectric response was observed in n-type perovskite oxide La(1-x)Ce(x)CoO(3). Combining transport and magnetic measurements, we found that the thermoelectric response is driven by the spin-state transition of Co(3+). This transition destroys the spin blockade effect and induces an abrupt decrease of resistivity as well as an insulator metal transition. In contrast to the resistivity change, changes in thermopower and thermal conductivity are moderate. Consequently, a peak of figure of the merit ZT is present in a narrow temperature range. The room-temperature ZT approximate to 0.018 of La(0.94)Ce(0.06)CoO(3) is comparable to that of p-type Na(x)CoO(2). These observations can be helpful for the search and design of new thermoelectric materials.