Low temperature synthesis, structure and properties of alkali-doped La₂NiO₄, LaNiO₃ and LaNi_0.85Cu_0.15O₃ from alkali hydroxide fluxes

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• 作者：Shivakumara ; C. ; Hegde ; M.S. ; Prakash ; A.S. ; Khadar ; A.M.A. ; Subbanna ; G.N. ; Lalla ; N.P.
• 关键词：Lanthanum nickel oxides ; Alkali hydroxide fluxes ; Cu-substituted LaNiO₃ ; Alkali metal substitution
• 刊名：Solid State Sciences
• 出版年：2003
• 出版时间：February, 2003
• 年：2003
• 卷：5
• 期：2
• 页码：351-357
• 全文大小：368 K

文摘

We report a low-temperature synthesis of La_1.95Na_0.05NiO₄ from NaOH flux, La_0.97K_0.03NiO₃ and La_0.95K_0.05Ni_0.85Cu_0.15O₃ phases from KOH flux at 400°C. Alkali-doped LaNiO₃ can be prepared in KOH, but not in NaOH flux and La₂NiO₄ can be prepared in NaOH, but not in KOH flux. The flux-grown oxides were characterized by powder X-ray Rietveld profile analysis and electron microscopy. Sodium doped La₂NiO₄ crystallizes in orthorhombic structure and potassium doped LaNiO₃-phases crystallizes in rhombohedral structure. La_1.95Na_0.05NiO₄ is weakly paramagnetic and semiconducting while La_0.97K_0.03NiO₃ and La_0.95K_0.05Ni_0.85Cu_0.15O₃ show Pauli paramagnetic and metallic behavior.