Thermoelectric power of hole-doped manganites:: La2-2xSr1+2xMn2O7 (0.3≤x≤0.5) -: art. no. 092407

We have investigated the hole doping effect on the thermoelectric power (S) of double layered manganites, La2 - 2xSr1 + 2xMn2O7, with nominal hole concentrations of x = 0.3, 0.4, and 0.5. A systematic change in the values of thermoelectric power was observed in the high-temperature range where samples were found to be paramagnetic and insulating. At low temperatures, not only the magnitude of S but also its temperature and magnetic-field dependency was found strongly influenced by a variation in x, reflecting the changes in their magnetic structures and the consequential charge-spin and charge-orbit coupling effects.