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Neutron diffraction studies of La4BaCu4MO13+δ (M = Ni and Co) oxides

2000; Elsevier BV; Volume: 35; Issue: 12 Linguagem: Inglês

10.1016/s0025-5408(00)00401-3

1873-4227

C. Shivakumara, M. S. Hegde, H. Rajagopal, A. Sequiera,

Advanced Condensed Matter Physics

Abstract The structures of La 4 BaCu 4 NiO 13.20 and La 4 BaCu 4 CoO 13.35 oxides synthesized in NaOH–KOH flux at 450°C were studied using powder neutron diffraction Rietveld analysis. These oxides crystallize in a tetragonal structure in the P 4/ m space group with Ni 3+ or Co 3+ partially occupying 6-coordinated (1a) and 5-coordinated (4j) sites of the La 4 BaCu 5 O 13+δ system. Increase in oxygen content with Ni and Co substitution is reflected in the increase in unit-cell volume, compared with that of the parent La 4 BaCu 5 O 13+δ .