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Highly sensitive lock-in thermoreflectance temperature measurement using thermochromic liquid crystal

Authors :
Atsushi Takahagi
Ryo Iguchi
Hosei Nagano
Ken-ichi Uchida
Source :
Applied Physics Letters. 122
Publication Year :
2023
Publisher :
AIP Publishing, 2023.

Abstract

We show that the temperature measurement sensitivity in the lock-in thermoreflectance (LITR) can be improved by incorporating a thermochromic liquid crystal (TLC) into a transducer. The quantitatively estimated thermoreflectance coefficient of a TLC/Pt hybrid film depends on the excitation frequency and reaches >2 × 10−2 K−1 at low excitation frequencies, which is two orders of magnitude greater than typical values of 10−4 for metallic films. Using the TLC/Pt film, we detected the temperature changes due to Joule heating and the spin Peltier effect with the temperature resolution of ∼10 μK by the LITR method. We also performed the same measurements for an Au film and found that the temperature resolution for the TLC/Pt film is increased by a factor of >10 compared with that for the Au film despite the low reflected light intensity of the TLC/Pt film.

Details

ISSN :
10773118 and 00036951
Volume :
122
Database :
OpenAIRE
Journal :
Applied Physics Letters
Accession number :
edsair.doi...........764614327f737ccf8d00b7bccbebc410
Full Text :
https://doi.org/10.1063/5.0142754