Influence of background oxygen pressure on film properties of pulsed laser deposited Y:BaZrO3

• Y:BaZrO3 (BZY) thin films by Pulsed laser deposition (PLD) were investigated.
• 4 BZY films were prepared by varying ambient oxygen pressure (Pamb,O2).
• Microstructural amorphous defects were formed at Pamb,O2 ≥ 13.3 Pa.
• In-grain and grain-boundary contributions were separated by electrochemical properties.
• Large impedances were identified from BZY films at Pamb,O2 ≥ 13.3 Pa.

Yttrium-doped barium zirconate (Y:BaZrO3, BZY) thin films were prepared using pulsed laser deposition (PLD) on MgO substrates at 700 °C by varying the ambient oxygen pressure. The microstructure and electrical properties were then investigated using transmission electron microscopy and electrochemical impedance spectroscopy. Dense, well-crystallized BZY films were produced at ambient oxygen pressures (Pamb,O2) of ≤ 6.67 Pa. At Pamb,O2 ≥ 13.3 Pa, conical amorphous defects and porous microstructures were observed in the films. The conductivity of PLD BZY prepared at Pamb,O2 ≤ 13.3 Pa was measured to be close to that of reference polycrystalline BZY films, and the grain-boundary properties governed the overall ion conduction, with nano-grains being covered by the space charge depletion zones. At Pamb,O2 ≥ 13.3 Pa, microstructural defects significantly degraded the electrical properties.