Magnetic influence on thermoelectric properties of CrO0.1N0.9

Thermoelectric polycrystalline chromium oxynitride CrO0.09(3)N0.90(7) (with cubic symmetry and space group Fm-3m) samples were successfully prepared by thermal ammonolysis of chromium oxide. This potential n-type thermoelectric material shows a temperature dependence of the Seebeck coefficient (S = −48 μV K−1 at 300 K) that is typical for degenerate semiconductors; the electrical resistivity (ρ300 ∼ 2.8 mΩ cm), however, is highly influenced by the grain boundaries and low density (∼60%) of the sample. The material exhibits a clear antiferromagnetic–paramagnetic transition simultaneously with an orthorhombic–cubic structural transition at TN = 262 K. The magnetic transition affected the material’s thermal conductivity, electrical resistivity, Seebeck coefficient, magnetic moment and specific heat. Heat capacity measurements at low temperatures revealed the predominance of the magnetic contribution due to spin waves.