A study of atomic and magnetic structure of La2/3Pb1/3Mn1-xCoxO3 using neutron and synchrotron diffraction methods

Abstract

The samples with nominal composition of La2/3Pb1/3Mn1-xCOxO3 (x = 0, 0.15, 0.20 and 0.25) were prepared by standard solid-state reaction method. Atomic and magnetic structures of the samples have been studied by neutron and synchrotron diffraction. The obtained results showed that, in wide temperature range (8-300 K) all investigated compounds are described by slightly distorted perovskite like structure with rhombohedral symmetry (sp. gr. R-3c). The lattice parameters and bond distances Mn/Co-O are typical of rhombohedral manganites. Type of ma^etic ordering doesn’t depend on doping level of Co: it is ferromagnetic at low temperahưe with average ordered value of magnetic moment in B-sites of about 3.5 Pb at r< 20 K.. In the compound with X = 0.15 there exist two crystal phases with the same symmetry but different stoichiometry. Only negligible changes of samples microstructure with composition were observed.