Magnetic and electronic properties of lead-doped lanthanum manganate

Abstract

Materials of nominal composition La_1–xPb_xMnO₃ (0.0≤x≤0.4) prepared by prolonged annealing at 950 °C, have been characterised by a combination of powder X-ray diffraction, energy dispersive X-ray microanalysis, thermogravimetry, atomic absorption spectroscopy and oxidising-power analysis. All phases adopt a rhombohedral variant of the perovskite structure and show significant 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 , close to T_C . Both T_C and T_MI show greater compositional variation than previously reported.