• On the magnetism, thermal- and electrical transport of ${\text{SrMoO}}_2\text{N}$

Physical properties of perovskite-type ${\text{SrMoO}}_2\text{N}$ phases were studied in the temperature range of $3\text{K}<T<300\text{K}$. The oxynitride crystallizes in a cubic unit cell (space group $Pm\overline{3}m$) 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 ${\text{SrMoO}}_2\text{N}$. Down to 150 K, the magnetic susceptibility is temperature independent and explained as enhanced Pauli paramagnetism $\left(\chi \sim {10}^{-4}\text{emu}{\text{mol}}^{-1}{\text{Oe}}^{-1}\right)$. The absolute value of its magnetic susceptibility is, however, half of that for ${\text{SrMoO}}_3$. Simultaneously, the lower Sommerfeld coefficient $\gamma$ measured for the oxynitride confirms the lower density of states near the Fermi level for ${\text{SrMoO}}_2\text{N}$ compared to ${\text{SrMoO}}_3$. At low temperature, both ${\text{SrMoO}}_2\text{N}$ and ${\text{SrMoO}}_3$ show Curie paramagnetism superimposed to the temperature independent Pauli paramagnetism and an anomaly at $T=54\text{K}$. 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.