Structure and impedance spectroscopy of Pr1−xSrxFe0.8Co0.2O3−δ (x=0.1, 0.2, 0.3) thin films grown by laser ablation

Polycrystalline samples of Pr 1− x Sr x Fe 0.8 Co 0.2 O 3− δ ( x =0.1, 0.2, 0.3) (PSFC) were prepared by the combustion synthesis route at 1200°C. The structure of the polycrystalline powders was analysed with X-ray powder diffraction data. The X-ray diffraction (XRD) patterns were indexed as the orthoferrite similar to that of PrFeO 3 having a single-phase orthorhombic perovskite structure (Pbnm). Pr 1− x Sr x Fe 0.8 Co 0.2 O 3− δ ( x =0.1, 0.2, 0.3) films have been deposited on yttria-stabilized zirconia (YSZ) single-crystal substrates at 700°C by pulsed laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes. The structure of the films was analysed by XRD, scanning electron microscopy (SEM) and atomic force microscopy (AFM). All films are polycrystalline with a marked texture and present pyramidal grains in the surface with different size distributions. Electrochemical impedance spectroscopy (EIS) measurements of PSFC/YSZ single crystal/PSFC test cells were conducted. The Pr 0.7 Sr 0.3 Fe 0.8 Co 0.2 O 3− δ film at 850°C presents a lower area specific resistance (ASR) value, 1.65 Ω cm 2 , followed by the Pr 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3− δ (2.29 Ω cm 2 at 850°C) and the Pr 0.9 Sr 0.1 Fe 0.8 Co 0.2 O 3− δ films (5.45 Ω cm 2 at 850°C).