Structural and electrical properties of the sol–gel prepared Sr1−xErxSnO3−δ compounds

Erbium-substituted strontium stannates, with Er content 0≤x≤0.09, have been prepared by sol–gel method. The solubility limit of Er was found to be about 3%. The influence of temperature and the duration of the calcination, on the confirmation of single phase of Er doped SrSnO3 were investigated by using X-ray powder diffraction. The distribution of Er3+ in the crystal structure has been studied. Rietveld refinement of the data revealed that the crystal structure of the representative compound (Sr0.97Er0.03SnO3−δ) is orthorhombic perovskite (space group Pbnm). The cell dimensions are: a=5.7152(1) Å, b=5.7092(1) Å and c=8.0710(2) Å. The IR spectroscopy measurements of the samples with x≤0.03 were done in a wavelength range 400–2000 cm−1 and confirmed the observed tilting in the SnO6 octahedra. The transport properties in the system Sr1−xErxSnO3−δ, x≤0.03, were investigated at high temperature. The Sr0.97Er0.03SnO3−δ compound exhibits semiconductive behaviour and the electrical transport mechanism agrees with the non-adiabatic small polaron hopping model between nominal states Sn4+/Sn2+ in the temperature ranges 350–525 and 525–693 K separately.