Infrared Radiation Detection With YBa sub 2 Cu sub 3 O sub 7--d Microbridge

• Published in: Japanese Journal of Applied Physics, Letters (Japan) Vol. 30; no. 12B; pp. 2091 - 2094
• Main Authors: Yotsuya, T, Imokawa, H, Yang, Q-S
• Format: Journal Article
• Language: English
• Published: 15.12.1991
• ISSN: 0021-4922

The photoresponse of YBa sub 2 Cu sub 3 O sub 7--d thin film with double bridges (DC-SQUID type) has been investigated under irradiation of weak laser light. The YBCO thin film of 200 nm thickness was prepared on a MgO(100) single-crystal substrate by an rf-magnetron sputtering method. It was processed to perform as a double microbridge (DC-SQUID type) patterned by ECR ion etching and then assembled as a YBCO thin-film sensor. The microbridge used was 5 mu m in width and 7.5 mu m in length. The sensitivity of the sensor was determined by irradiating a modulated laser light (modulating frequency of 17-400 Hz, wavelength of 827 nm). The device showed both bolometric and nonbolometric behavior in the superconducting transition region. The maximum noise equivalent power (NEP) and responsivity was obtained at 76K, and was 5 x 10 exp --9 W/Hz exp 1/3 and 19 V/W, respectively. The nonbolometric response was caused by vortex motion.