Magnetic and transport characteristics of oxygenated polycrystalline La0.6Pb0.4MnO3

A polycrystalline La0.6Pb0.4MnO3 sample, demonstrating predominantly a single phase behavior (hexagonal structure (R-3c) with the lattice parameters a=b=5.5009 (4)Å, c=13.3744 (10)Å, α=β=90°, γ=120°) was prepared by solid state reaction in oxygen atmosphere. A second pelletization and sintering processes assisted in a closer packing of the grains in the sample. The saturation and spontaneous magnetizations of the sample, measured at 4K and 300K were Msat=75.8emu/g, 48emu/g and Ms=66.2emu/g, 26emu/g, respectively. The sample demonstrated a relatively high magneto-resistance effect (−32.3% at 4K and 10kOe). The resistance R showed a small progressive decrease in cyclic magnetic field H at 300K and a hysteresis arose in the R vs H dependence at low temperatures. ► Oxygenated polycrystalline La0.6Pb0.4MnO3 by solid state reaction was performed. ► Closely packed grains with hexagonal structure (R-3c) were formed. ► Relatively high magneto-resistance effect (−32.3% at 4K and 10kOe) was obtained. ► An observable hysteresis arose in the R vs H dependence measured at low temperatures. ► The values of magnetization were of the same order as those of the single crystals.