1 July 1991 Performance characteristics of Y-Ba-Cu-O microwave superconducting detectors
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Abstract
Identifies a high-Tc temperature-transition edge, nonbolometric detector response in microstrip line device structures fabricated from thin films of Y1Ba2Cu3O7-x deposited on MgO single crystal substrates. Such detectors have an intrinsically fast response and in principle are capable of operating up to frequencies represented by the superconducting energy gap (terahertz region), if such an energy gap concept is applicable to these unique materials. The detector output, a dc output voltage across the device, is function of bias current and temperature, with an optimum temperature in the vicinity of the point at which zero resistance is reached (To). The mechanism for the detector action is believed to be related to the switching of the superconductor from its superconducting state to its normal state, driven by the input radiation, while the superconductor is held at a suitable current bias point and temperature. Both films made by the laser ablation process and chemical spray pyrolysis form detector elements. However, the films formed by these two techniques are vastly different morphologically. The extent to which film morphology influences detector performance has been examined in an effort to examine the so-called weak-link question. The Noise Equivalent Power (NEP) of a laser ablated detector has been estimated to be below -80 dbm for an operating condition of 70 K, frequency of 8 GHz and modulation of 60 KHz. The measurement limitation is extrinsic noise, and it is believed that these devices are extremely low noise, far better than possible with conventional Schottky diodes/p-n junctions, or Josephson-like SIS structures for that matter. Various other performance characteristics are presented, along with a suggested NSN model for electrical conduction.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John Shewchun, P. F. Marsh, "Performance characteristics of Y-Ba-Cu-O microwave superconducting detectors", Proc. SPIE 1477, Superconductivity Applications for Infrared and Microwave Devices II, (1 July 1991); doi: 10.1117/12.45613; https://doi.org/10.1117/12.45613
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