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Abstract

Monoclinic BaIrO3BaIrO3 was reported to display simultaneous onset of charge density wave transition (CDW) and weak ferromagnetic ordering of Ir moments at View the MathML sourceTc=175K. In this work, we present heat capacity, resistivity, thermopower and thermal conductivity measurements on a high-quality polycrystalline BaIrO3BaIrO3 sample. The specific heat evidences a well defined mean field like anomaly, much larger than that reported for a single crystal, and at a slightly higher View the MathML sourceTc=183K. The increase of the resistivity below TcTc is also much larger than in previous investigation, and the semiconducting behavior at low temperature is much more pronounced. The onset of the CDW leads to a strong increase of the thermopower, from a few μV/KμV/K above TcTc up to nearly View the MathML source300μV/K at 70 K, supporting a strong decrease of the charge carrier density and the opening of a gap at TcTc. In contrast, no anomaly is observed at TcTc in the thermal conductivity, which is dominated by phonon contributions.