Synthesis, crystal structure, and valence states of Mn-substituted La2RuO5

Article

关键词: SCIENCE-AND-TECHNOLOGY;    HIGH-TEMPERATURE;    MAGNETIC-PROPERTIES;    HEXAGONAL PEROVSKITES;    POWDER DIFFRACTOMETER;    DIFFRACTION;    RU;    SUPEREXCHANGE;    LA1.2SR1.8MN2-XRUXO7;    SPECTROSCOPY;   

DOI  :  10.1103/PhysRevB.90.024406

来源: SCIE

【 摘 要 】

Polycrystalline samples of layered perovskite-related La2Ru1-yMnyO5 (0 <= y <= 0.25) were prepared by a soft-chemistry synthesis based on the thermal decomposition of a citrate precursor. The crystal structures of the compounds were determined by Rietveld analysis of x-ray diffraction patterns recorded at different temperatures. Additional neutron diffraction patterns for La2Ru0.75Mn0.25O5 were recorded between 1.5 K and 300 K. A structural phase transition from a monoclinic room-temperature to a triclinic low-temperature phase was observed for y <= 0.20, while for y = 0.25 a phase separation at low temperatures was identified. The structural phase-transition temperatures decrease with increasing Mn concentration. Selected area electron diffraction of La2Ru0.75Mn0.25O5 documented the absence of cationic ordering of Ru and Mn. The Mn and Ru oxidation states were determined using x-ray absorption spectroscopy and showed a stable +4 valence for both elements in all samples investigated, at room temperature as well as at 110 K.

【 授权许可】

Free