Tuning of Structure, Morphology and Magnetism in Postperovskite Oxide Solid Solutions

High-quality polycrystalline samples of postperovskite type CaIr1−x Pt x O3 solid solutions (x = 0.3, 0.5, 0.7) and CaIr0.5Rh0.5O3 have been synthesized at a pressure of 15 GPa, and their structures and properties are compared with those of CaIrO3. Substantial [100] grain growth is observed in all s...

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Veröffentlicht in:Chemistry of materials 2011-01, Vol.23 (1), p.114-121
Hauptverfasser: Hirai, Shigeto, Sanehira, Takeshi, Nishiyama, Norimasa, Irifune, Tetsuo, Klemme, Stephan, Bromiley, Geoffrey, Attfield, J. Paul
Format: Artikel
Sprache:eng
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Zusammenfassung:High-quality polycrystalline samples of postperovskite type CaIr1−x Pt x O3 solid solutions (x = 0.3, 0.5, 0.7) and CaIr0.5Rh0.5O3 have been synthesized at a pressure of 15 GPa, and their structures and properties are compared with those of CaIrO3. Substantial [100] grain growth is observed in all samples, leading to pronounced texture even in powdered materials. Small changes in the lattice constants and octahedral distortions are observed across the CaIr1−x Pt x O3 series. CaIrO3 is semiconducting and shows temperature-independent paramagnetism and an ordered moment of 0.04 μB below a 108 K magnetic transition. Doping with Pt or Rh induces Curie−Weiss paramagnetism and suppresses the magnetic transition to zero for ∼40% Pt doping. The anisotropic structure and morphology of CaIrO3 combined with the Ir4+ spin−orbit coupling results in a large magnetic anisotropy constant of 1.77 × 106 J m−3, comparable to values for permanent magnet materials.
ISSN:0897-4756
1520-5002
DOI:10.1021/cm102660q