Magnetic and conductive properties of La_0.5Pb_0.5MnO₃

The magnetic and conductive properties of polycrystalline La_0.5Pb_0.5MnO₃ containing ∼13at.% of a second phase Pb₃Mn₆O₁₃, were investigated. The studies reported include measurements of magnetization, electrical resistivity and magnetoresistance, in a temperature range 10 ÷ 400 K and at applied magnetic fields up to 5 Tesla It was found that the sample exhibits a ferromagnetic ordering with relatively low coercive field at room temperature. Measurements of field-cooled and reversed-field-cooled magnetization support models of coexisting magnetic phases in ferromagnetic La-based manganites The resistivity measured exhibits a maximum at ∼ 230 K and a broad shallow minimum at ∼ 20÷25 K. These features are also attributed to the temperature dependence of the magnetic inhomogeneities. Measurements of magnetoresistance show a characteristic giant effect at low temperatures.