Thermal Diffusivity and Acoustic Properties of Nb Thin Films Studied by Time-Domain Thermoreflectance

Authors

Md. Obidul Islam, Old Dominion UniversityFollow
Hani Elsayed-Ali, Old Dominion UniversityFollow

Document Type

Conference Paper

Publication Date

2024

DOI

10.18429/JACoW-IPAC2024-THPR63

Publication Title

Proceedings of the 15th International Particle Accelerator Conference

Pages

3667-3670

Conference Name

15th International Particle Accelerator Conference, 19-24 May 2024, Nashville, TN

Abstract

The thermal diffusion and acoustic properties of Nb impacts the thermal management of devices incorporating Nb thin films such as superconducting radiofrequency (SRF) cavities and superconducting high-speed electronic devices. The diffusion and acoustic properties of 200-800 nm thick Nb films deposited on Cu substrates were investigated using time-domain thermoreflectance (TDTR). The films were examined by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The grain size and thermal diffusivity increase with film thickness. The thermal diffusivity increased from 0.100± 0.002 cm²s^-1 to 0.237± 0.002 cm²s^-1 with the increase in film thickness from 200 nm (grain size 20±6 nm) to 800 nm (grain size 65±16 nm). Damped periodic photoacoustic signals are detected due to laser heating generated stress in the Nb film, which results in an acoustic pulse bouncing from the Nb/Cu and the Nb/vacuum interfaces. The period of the acoustic oscillation gives a longitudinal sound velocity of 3637.3 ms^-1 inside the Nb films, which is in good agreement with the values reported in the literature.

Rights

© 2024 The Authors.

Published under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License. Any further distribution of this work must maintain attribution to the authors, the published article's title, publisher, and DOI.

Original Publication Citation

Islam, M., & Elsayed-Ali, H. (2024) Thermal diffusivity and acoustic properties of Nb thin films studied by time-domain and thermoreflectance. In F. Pilat, W. Fischer, R. Saethre, P. Anisimov, & I. Andrian (Eds.), Proceedings of the 15th International Particle Accelerator Conference. JACoW. https://doi.org/10.18429/JACoW-IPAC2024-THPR63

Repository Citation

Islam, Md. Obidul and Elsayed-Ali, Hani, "Thermal Diffusivity and Acoustic Properties of Nb Thin Films Studied by Time-Domain Thermoreflectance" (2024). Electrical & Computer Engineering Faculty Publications. 479.
https://digitalcommons.odu.edu/ece_fac_pubs/479

ORCID

0000-0003-1313-4617 (Islam), 0000-0002-1329-5018 (Elsayed-Ali)