MAGNETIC AND ELECTRONIC-PROPERTIES OF LEAD-DOPED LANTHANUM MANGANATE

Materials of nominal composition La1-xPbxMnO3 (0.0 less than or equal to x less than or equal to 0.4) prepared by prolonged annealing at 950 degrees C, have been characterised by a combination of powder X-ray d iffraction, energy dispersive X-ray microanalysis, thermogravimetry, a tomic absorption spectroscopy and oxidising-power analysis. All phases adopt a rhombohedral variant of the perovskite structure and show sig nificant deviations from nominal stoichiometries. All doped materials exhibit ferromagnetic ordering at a temperature, T-C, close to ambient and undergo a metal-insulator transition at a temperature, T-MI, clos e to T-C. Both T-C and T-MI show greater compositional variation than previously reported.