2024/03/10 by Amani Jayakody, J. I. Budnick, Jayakody, Amani S. +7
Materials Science · #Catalytic Processes in Materials Science #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2403.06305
openalex publication_date 2024/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Bulk Scandium trifluoride (ScF3) is known for a pronounced negative thermal expansion (NTE) over a wide range of temperature, from 10~K~to~ 1100~K. The structure of ScF3 can be described as an ABX3 perovskite with an empty A-site and a space group of Pm-3m. Growing thin films of ScF3 allows for tuning the lattice constant, the thermal expansion, and the construction of devices based upon differential thermal expansion. We have investigated the growth of ScF3 films on oxide and fluoride substrates using pulsed laser deposition (PLD) This letter describes the successful growth recipe for producing high quality epitaxial ScF3 thin films on positive thermal expansion (PTE) lithium fluoride (LiF) substrates, at substrate temperature, 350∘C with a laser repetition rate of 1~Hz, with an energy per pulse of 600~mJ, under a vacuum of 1.5× 10-6~ torr, for a growth time of 6 hours. However, even for films with excellent epitaxy and sharp peaks along the principal axes, diffraction peaks from certain crystallographic directions are extremely broad, with the example of (104) reflections, in this work. We attribute this broadening to disorder in the F6 octahedral rotations that occur as an attempt to accommodate the large temperature-induced lattice mismatch that results in cooling from the growth temperature for this system of a NTE film mated to a PTE substrate.