Apparent anisotropic thermal diffusivity measured in cubic single crystals by transient grating spectroscopy

0572000 - ÚT 2024 RIV US eng J - Journal Article
Kušnír, J. - Grabec, Tomáš - Zoubková, K. - Stoklasová, Pavla - Sedlák, Petr - Seiner, Hanuš
Apparent anisotropic thermal diffusivity measured in cubic single crystals by transient grating spectroscopy.
Journal of Applied Physics. Roč. 133, č. 12 (2023), č. článku 125108. ISSN 0021-8979. E-ISSN 1089-7550
R&D Projects: GA ČR(CZ) GA22-13462S
Institutional support: RVO:61388998
Keywords : signal processing method * crystal structure * elastic modulus * materials properties * transient grating spectroscopy * finite-element analysis * optical metrology * lasers * thermal diffusivity
OECD category: Acoustics
Impact factor: 3.2, year: 2022
Method of publishing: Open access
https://pubs.aip.org/aip/jap/article/133/12/125108/2881424

The effect of elastic anisotropy on thermal diffusivity determination by transient grating spectroscopy (TGS) was studied. In experiments performed on a set of cubic single crystals, it was observed that TGS measurements may indicate anisotropy of thermal diffusivity in otherwise thermally isotropic materials, and that the strength of this apparent anisotropy is correlated with the strength of the elastic anisotropy. To find a source of the observed phenomenon, finite-element simulations of the TGS measurements were carried out. Time-domain TGS signals were generated from the simulations and processed identically to the experimental data. The simulation results revealed that the elastic anisotropy affects the detected time-domain signals. Consequently, the thermal diffusivity coefficients determined from them showed the artificial directional dependence.
Permanent Link: https://hdl.handle.net/11104/0342849