The electrical resistivity and thermoelectric power of the europium (II) niobium bronzes, EuxNbO3, were measured as a function of europium concentration from x = 0.51-0.92 over temperatures of 4.2-373 K. All samples in tetragonal form (x = 0.51-0.65) showed semiconducting conduction, while the samples in cubic form (x = 0.65-0.92) exhibited metallic conduction. A Goodenough model for the tungsten bronze, NaxWO3, was employed for the difference in the electrical conduction behavior between the two bronzes. Residual drift mobility for the cubic bronze decreased with x except for x — 0.76 and on this point an irregularly high value was obtained. The temperature-dependent part of the drift mobility for the cubic one was found to be describable by the perturbation theory of Howarth and Sondheimer. An effective mass of the electron for each cubic bronze was about 2m0 (m0 is the electronic rest mass), and the quasi-free electron model was roughly applicable.
- electrical resistivity
- thermoelectric power