On the magnetism, thermal- and electrical transport of SrMoO2N

Physical properties of perovskite-type SrMoO2N phases were studied in the temperature range of 3 K < T < 300 K. The oxynitride crystallizes in a cubic unit cell (space group Pm (3) over barm) as revealed by neutron and x-ray diffraction measurements. The polycrystalline material shows weakly temperature dependent electrical resistivity and low glasslike heat conductivity, both reflecting the unusual strength of the scattering processes in the charge carrier transport. Based on the positive Seebeck coefficient values, holes are identified as the dominating charge carriers in SrMoO2N. Down to 150 K, the magnetic susceptibility is temperature independent and explained as enhanced Pauli paramagnetism (x similar to 10(-4) emu mol(-1) Oe(-1)). The absolute value of its magnetic susceptibility is, however, half of that for SrMoO3. Simultaneously, the lower Sommerfeld coefficient gamma measured for the oxynitride confirms the lower density of states near the Fermi level for SrMoO2N compared to SrMoO3. At low temperature, both SrMoO2N and SrMoO3 show Curie paramagnetism superimposed to the temperature independent Pauli paramagnetism and an anomaly at T=54 K. This anomaly is attributed to the presence of molecular oxygen in the material, while the Curie upturn is likely associated with a small amount of paramagnetic centers. (c) 2009 American Institute of Physics. [DOI: 10.1063/1.3067755]