Oral Presentation

Dielectric Properties of MgO, Al2O3 and LaAlO3 from 0.22 to 3THz at Different Temperatures (Remote)

Author(s): Jiameng Wang, Kangmin Zhou, Bowen Fan, Zhi Li, Jie Hu, Qiang Zhi, Siyuan Zhao, Jing Li, Shengcai Shi

Presenter: Jiameng Wang (Purple Mountain Observatory, CAS)

With moderate cooling requirements, YBCO-based
superconducting detectors are promising for space applications
from microwave to the terahertz regime. Their sensitivities,
however, are still rather limited. The dielectric loss of the substrate
on which YBCO films are deposited might play an important role
in the detector performance. This study systematically
characterizes the dielectric properties of three common
commercially available substrates for YBCO film, i.e., Sapphire
(Al2O3), Lanthanum aluminate (LaAlO3), and Magnesium oxide
(MgO), from 0.22 to 3 THz at 300 K, 77 K, and 20 K. It has been
found that both Al2O3 and MgO substrates exhibit significantly
reduced loss tangents (tanδ < 1×10-5) at cryogenic temperatures
(77 K and 20 K), whereas LaAlO3 maintains high dielectric loss
tangents (tanδ > 3×10-3) across all measured temperatures and
frequencies.