Ba2Ir3O9: a new 5d mixed-valence metallic oxide with KSbO3-type structure

摘要: Abstract Crystal structure, magnetic and transport properties of new ternary mixed-valence iridium oxide Ba 2 Ir 3 O 9 are reported. A hydrothermal reaction IrO BaO under a pressure 150 MPa at 650 °C yields small black crystals with cubic shape. Energy dispersive X-ray analysis on an as-grown crystal gives the atomic ratio Ba:Ir = 2:3. powder diffraction shows pattern lattice cell parameter 9.42 A further Rietveld reveals KSbO -related structure. Although structure is almost identical to 0.5 [Mat. Res. Bull. (1974) 1777], there significant difference in composition between them. Because crystallographic site for unique, classified into class III compound where average valence +4.67. The susceptibility temperature independent Pauli paramagnetism 2.9 × 10 −4  emu/mol room temperature. resistivity pellet sample measured be 1.5 −1  Ω cm metallic dependence. At low temperature, dependent component proportional T . This indicates that bad metal because strong electron-electron scattering. narrow 5d-band feature characteristic -type related electron correlation.