Effect of Sn doping on sinterability and electrical conductivity of strontium hafnate

The effect of isovalent substitution of hafnium by tin in strontium hafnate on sinterability and electrical conductivity was studied for the first time. The ceramic samples SrHfxSn1–xO3–δ (x = 0–0.16) were synthesized by solid-state reaction and sintered at 1600 °C for 5 h. The samples were examined using the methods of X-ray diffraction, scanning electron microscopy, impedance spectroscopy, and four-probe direct current technique. It was shown that all samples were phase pure and had the orthorhombic structure of SrHfO3 with the Pnma space group. Sn doping resulted in an increase in grain size, relative density and conductivity; the sample with x = 0.08 demonstrated the highest conductivity, which was ~830 times greater than that of undoped strontium hafnate at 600 °C. The conductivity of SrHf0.92Sn0.08O3–δ was 4.1∙10–6 S cm–1 at 800 °C in dry air. The possible reasons for the effect of Sn on the electrical properties of strontium hafnate were discussed.