Characterization and design of a low-noise second-order gradient SQUID with asymmetric shunt resistors
Abstract
A low-noise superconducting quantum interference device (dc-SQUID) with simplified design and readout electronics is highly desirable for various applications. We demonstrate that introducing an asymmetric shunt resistor significantly enhances the noise performance while maintaining the inherent simplicity and tunability of the SQUID design. By optimizing the asymmetry factor, our asymmetric shunted second-order gradient SQUID current sensor reaches a low white flux noise of 0.65 μΦ0/√Hz using a direct readout strategy, representing a threefold improvement over its symmetric counterpart. This noise level surpasses that of the SQUID with the additional positive feedback method and is comparable to the series SQUID arrays, making the asymmetric shunted SQUID suitable for meeting the readout requirements of various scientific instruments.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (7)
Yuxiao Guo
National Institute of Metrology , Beijing 102200,
Jinjin Li
College of Chemistry and Environmental Science
Xiaolong Xu
Shijian Wang
Centre for Clean Energy Technology, Faculty of Science
Xueshen Wang
National Institute of Metrology , Beijing 102200,
Jian Chen
Qing Zhong