Synthesis, Crystal Structure, and Electronic Properties of High-Pressure PdF2-Type Oxides MO2 (M = Ru, Rh, Os, Ir, Pt)
文摘
The polycrystalline MO2鈥檚 (HP-PdF2-type MO2, M = Rh, Os, Pt) with high-pressure PdF2 compounds were successfully synthesized under high-pressure conditions for the first time, to the best of our knowledge. The crystal structures and electromagnetic properties were studied. Previously unreported electronic properties of the polycrystalline HP-PdF2-type RuO2 and IrO2 were also studied. The refined structures clearly indicated that all compounds crystallized into the HP-PdF2-type structure, M4+O2鈥?/sup>2, rather than the pyrite-type structure, Mn+(O2)n鈭?/sup> (n < 4). The MO2 compounds (M = Ru, Rh, Os, Ir) exhibited metallic conduction, while PtO2 was highly insulating, probably because of the fully occupied t2g band. Neither superconductivity nor a magnetic transition was detected down to a temperature of 2 K, unlike the case of 3d transition metal chalcogenide pyrites.