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Pd(111) thin films, ∼245 nm thick, are deposited on Al₂O₃(0001) substrates at ≈0.5T_m, where T_m is the Pd melting point, by ultrahigh vacuum dc magnetron sputtering of Pd target in pure Ar discharges. Auger electron spectra and low-energy electron diffraction patterns acquired in situ from the as-deposited samples reveal that the surfaces are compositionally pure 111-oriented Pd. Double-axis x-ray diffraction (XRD) Ó¬-2θ scans show only the set of Pd 111 peaks from the film. In triple-axis high-resolution XRD, the full width at half maximum intensity Γ_Ó¬ of the Pd 111 Ó¬-rocking curve is 630 arc sec. XRD 111 pole figure obtained from the sample revealed six peaks 60°-apart at a tilt angles corresponding to Pd 111 reflections. XRD φ scans show six 60°-rotated 111 peaks of Pd at the same φ angles for 11 23 of Al₂O₃ based on which the epitaxial crystallographic relationships between the film and the substrate are determined as (111)Pd∥ (0001)Al2O3 with two in-plane orientations of [112]Pd∥ [1120]Al2O3 and [211]Pd∥ [1120]Al2O3. Using triple axis symmetric and asymmetric reciprocal space maps, interplanar spacings of out-of-plane (111) and in-plane (11 2) are found to be 0.2242 ± 0.0003 and 0.1591 ± 0.0003 nm, respectively. These values are 0.18% lower than 0.2246 nm for (111) and the same, within the measurement uncertainties, as 0.1588 nm for (11 2) calculated from the bulk Pd lattice parameter, suggesting a small out-of-plane compressive strain and an in-plane tensile strain related to the thermal strain upon cooling the sample from the deposition temperature to room temperature. High-resolution cross-sectional transmission electron microscopy coupled with energy dispersive x-ray spectra obtained from the Pd(111)/Al₂O₃(0001) samples indicate that the Pd-Al₂O₃ interfaces are essentially atomically abrupt and dislocation-free. These results demonstrate the growth of epitaxial Pd thin films with (111) out-of-plane orientation with low mosaicity on Al₂O₃(0001).