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Applying Dynamic Strain on Thin Oxide Films Immobilized on a Pseudoelastic Nickel-Titanium Alloy
Published on: July 28, 2020
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Dynamic strain evolution in an optically excited Pt thin film
M F DeCamp1, A D DiChiara2, K M Unruh1
1Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA.
AIP Advances
|November 12, 2021
Summary
Ultrafast laser pulses induce structural changes in platinum films. Below 50 mJ/cm², reversible lattice expansion occurs, while higher fluences cause irreversible stress relaxation and altered structural evolution.
Area of Science:
- Materials Science
- Surface Science
- Nanotechnology
Background:
- Platinum (Pt) thin films are crucial in catalysis and electronics.
- Understanding their structural dynamics under laser irradiation is key for advanced applications.
- Photo-thermal effects play a significant role in material modification.
Purpose of the Study:
- To investigate the structural evolution of Pt thin films after ultrafast photo-thermal excitation.
- To determine the influence of laser pulse fluence on stress relaxation and lattice dynamics.
- To establish the time-resolved response of Pt films to ps laser pulses.
Main Methods:
- Time-resolved structural analysis using ultrafast optical laser pulses (1 ps).
- High time resolution (100 ps) measurements over 1 ms.
- Variable laser pulse fluences (below and above 50 mJ/cm²).
Main Results:
- Low fluences (<50 mJ/cm²) caused reversible lattice expansion and decreased coherence length within 100-200 ps.
- High fluences (>50 mJ/cm²) induced irreversible stress relaxation and altered lattice coherence evolution.
- Structural recovery was observed at low fluences, but not at high fluences.
Conclusions:
- Laser fluence dictates the reversibility of structural changes in Pt thin films.
- Ultrafast photo-thermal effects can be harnessed for controlled material modification.
- The study provides insights into laser-induced stress relaxation mechanisms in metallic thin films.
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