Temperature Dependent Optical Response Of High- Tc Yba2cu3o7-{\delta} (Ybco) Thin Films

TL;DR

This study investigates how the optical properties of YBCO thin films change with temperature near the superconducting transition, revealing potential for optical Tc detection using visible light.

Contribution

It demonstrates the temperature and wavelength dependence of optical transmittance and reflectance in YBCO thin films, linking optical response changes directly to superconducting phase transition.

Findings

Transmittance increases near Tc, saturating a few kelvins below.

Reflectance decreases as temperature drops below Tc.

Maximum optical variation occurs at 633 nm, minimal at 450 nm.

Abstract

We report on the temperature-dependent optical response of thin films of YBa2Cu3O7-{\delta} (YBCO) in the visible spectral range under cryogenic conditions. Specifically, we observe an increase in transmittance near the superconducting transition temperature (Tc), which saturates within a few kelvins below Tc. The increase in transmittance is accompanied by a corresponding decrease in reflectance as the temperature drops below Tc, and both quantities track the superconducting phase transition. Changes in transmittance are found to be wavelength dependent, with the maximum variation occurring at 633 nm and minimal at 450 nm. These observations establish a correlation between the variation in optical response and the superconducting phase transition, even in the visible regime. The results of our experiment highlight the potential for using non-contact optical measurements to determine Tc. The effect can be explained using the two-fluid model, which can account for the observed temperature and wavelength dependence of the transmittance of the superconducting thin films.