Polycrystalline samples of La 2 MMnO 6 (M = Co and Mg) were prepared by a combined gel-combustion and high temperature reaction method. The samples were annealed in different oxygen partial pressure (p O2 ) and characterized by powder XRD, SQUID magnetometry, ac impedance spectroscopy, and electron paramagnetic resonance techniques. Monoclinic (P2 1 /n) and rhombohedral (R3) lattices were observed for La 2 CoMnO 6 and La 2 MgMnO 6 , respectively. On annealing in inert atmosphere, La 2 MgMnO 6 partially converted to monoclinic La 2 CoMnO 6 type structure, whereas no structural change was observed in La 2 CoMnO 6 .

No abstract

No abstract

The present study describes the structural and luminescent properties of SrSnO(3) nanorods containing Eu(3+) ions. Based on Rietveld refinement of XRD patterns corresponding to both undoped and europium doped SrSnO(3) nanorods, it is inferred that the average bond lengths of Sr-O1 linkages, which have a square planar geometry around Sr(2+) in the SrO(12) polyhedra present in SrSnO(3), remained unaffected with Eu(3+) incorporation into the lattice. However, the average bond lengths of shorter Sr-O2 linkages increase and longer Sr-O2 linkages decrease with Eu(3+) doping into the SrSnO(3) lattice. A lack of variation in the lattice parameters of SrSnO(3) with doped Eu(3+) ions is explained based on mutually compensating changes in the average bond lengths of the Sr-O2 linkages in the unit cell. Luminescence studies have confirmed that Eu(3+) ions occupy the centrosymmetric Sr(2+) site only up to 2 at%, beyond which Eu(3+) ions exist in a significantly distorted environment (grain boundaries). Beyond 3%, incorporation of Eu(3+) ions into the SrSnO(3) lattice leads to the formation of a Eu(2)Sn(2)O(7) phase. From the EPR studies it is confirmed that around 5% of the incorporated Eu(3+) ions get converted to Eu(2+) ions and they occupy Sr(2+) sites in the lattice.

No abstract