The production and characterization of lanthanum-doped tungsten oxide, , sintered samples are presented for . The x-ray diffraction results show that the cubic perovskite phase is stable for in the range of 0.086–0.21. Outside of this range additional phases are present. Resistivity measurements made between 64 and provide information on the electronic properties. Room temperature Hall effect results show that the trivalent La ions donate their valence electrons into the conduction band. The samples have been prepared for an investigation of the metal-insulator transition in this tungsten bronze system.
REFERENCES
The expression relating the sample and crystal conductivities may also be obtained as follows. The sample conductivity depends on the crystal volume fraction , with . Putting , where and are measured for a particular sample, and using a linear extrapolation to , we have the estimate .
