ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
One can use a direct current (dc) superconducting quantum interference device (SQUID) as a current amplifier by injecting a signal current Is into part of the superconducting loop and detecting the resultant change in critical current Ic. The current gain max ||dIc/dIs|| can be increased by making the inductances of the two arms of the SQUID asymmetric, thereby skewing the transfer function Ic vs Is. Detailed simulations of the device performance include an analysis of the impact of inductance and junction asymmetry on the transfer function. At 77 K a maximum current gain of 5 should be achievable albeit for frequencies below 1 GHz. An increase in the operating speed to 2 GHz can be achieved by reducing the gain to 2. We have fabricated asymmetric YBa2Cu3O7−x dc SQUIDs on SrTiO3 bicrystal substrates and operated them at 77 K. Using a second, readout SQUID to monitor changes in the critical current, we have achieved a low-frequency current gain up to 2.3. By coupling two SQUIDs together, we have increased the gain to 8.5. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.360911
