Abstract
The study of nonbolometric responses caused by the vortex motion and other factors of YBa2Cu3O7-δ (YBCO) microbridges has received much attention because of possible applications for sensitive and fast response detectors. In this study, we fabricated a slot antenna-coupled YBCO microbridge and investigated IF properties at 94 GHz to evaluate the response speed of the device in the resistive state. The response mechanism of the device biased in the resistive state consists of the bolometric response and the nonbolometric response caused by the flux creep and flux flow. From the measurements of voltage-current (I-V) characteristics and video detection properties, the response mechanism was investigated and operating conditions that dominated the bolometric and nonbolometric responses were obtained. The IF bandwidth of the device, having its response dominated by the bolometric process, showed a constant value of about 60 MHz and did not depend on the bias current. On the other hand, the bandwidth dominated by the flux flow response increased as the bias current and temperature increased, up to 1.2 GHz, and depended on the vortex velocity.
