A High-Balance Planar SQUID Gradiometer

被引：12

作者：

Zhang, Xue ^{[1
,2
]}

Zhang, Guofeng ^{[1
,3
]}

Wang, Yongliang ^{[1
,3
]}

Rong, Liangliang ^{[1
,3
]}

Zhang, Shulin ^{[1
,3
]}

Wu, Jun ^{[1
,3
]}

Qiu, Longqing ^{[1
,3
]}

Xie, Xiaoming ^{[1
,3
]}

Wang, Zhen ^{[1
,3
]}

机构：

[1] Chinese Acad Sci, Shanghai Inst Microsyst & Informat Technol, State Key Lab Funct Mat Informat, Shanghai 200050, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

[3] Chinese Acad Sci, Ctr Excellence Superconducting Elect, Shanghai 200050, Peoples R China

来源：

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY | 2019年 / 29卷 / 05期

基金：

中国国家自然科学基金;

关键词：

Josephson device fabrication; Josephson device measurements; SQUIDs; SQUID designs and applications;

D O I：

10.1109/TASC.2019.2898678

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

We have developed and fabricated SQUID gradiometers in a Nb/Al-AlOx/Nb technology using an i-line stepper combined with a mask aligner lithography. The stepper and the aligner are used to fabricate fine-scale patterns such as the Josephson junctions and large-scale patterns such as pickup coil, respectively, on the same wafer with a 4-inch diameter. The SQUID is designed as a first-order gradiometer with a dual-washer configuration. Two sets of multiturn spiral input coils with opposite directions are integrated on the washer and connected to the pickup coil to form a flux transformer. In order to improve the balance of the gradiometer, a fully symmetric configuration is introduced with a mirrored SQUID. The pickup coil is a first-order gradiometric type with a base line of 3.5 cm. The size of each loop is 12.65 mm X 11.65 mm, which results in a gradient magnetic field sensitivity of 0.25 nT/(cm.Phi(0)). The measured gradient magnetic field noise is 75 fT/(m.root Hz) in the white noise region. Moreover, a sapphire holder is used to fix and package the chip in order to maintain the high intrinsic balance (typical 10(-4)). It makes the SQUID gradiometer more attractive for an unshielded operation in noisy environments.

引用

页数：3

共 6 条

[1] First-order planar superconducting quantum interference device gradiometers with long baseline [J].