Berlin 2024 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 20: Poster II
DS 20.6: Poster
Donnerstag, 21. März 2024, 18:00–20:30, Poster D
Watching hydrogen diffusion into Lutetium thin films with thin Pd cap layers — •Zahra Hojjati1,2, Harald Giessen1,2, and Philipp Flad1 — 14th Physics Institute — 2Stuttgart Research Center of Photonic Engineering
Hydrogenated Lutetium is one of the materials that might have a potential to be used as high-temperature superconductor under high pressure. Recently three have been reports that the system Lu-H-N undergoes a phase transition to blue when hydrogenated, and unconfirmed reports indicate superconductivity. We therefore investigate hydrogen-lutetium interactions and the dynamics of hydrogen diffusion within lutetium, which is influenced by the ambient temperature, the crystal structure and the hydrogen concentration. Hydrogen diffusion in metals involves interstitial diffusion through the lattice and surface absorption. We use samples that consists of a thin Lutetium film with a stripe of Palladium as a catalyst on top. They were placed in a gas cell with 10% H2 in N2. The sample was heated to 70-80 degrees Celsius in the presence of H2. The Lutetium-Palladium surface is getting dark within minutes. The color in Lutetium close to the Pd changes to blue, and this hydrogenation front advances over hours and days. Eventually, the Lutetium-Pd surface is transformed from black to brown, exhibiting cracks. We analyze the progression of the blue hydrogenation front in Lutetium was measured, and our evaluation indicates a drift rather than a diffusion process. We determine drift velocity and the detailed hydrogenation dynamics, which is important for advancements in energy storage technology.
Keywords: hydrogen diffusion; Lutetium; high-temperature superconductor; Palladium; hydrogen storage