Investigation of multiple SQUID arrangements in single layer high T/sub c/ magnetometers
Investigation of multiple SQUID arrangements in single layer high T/sub c/ magnetometers
复制标题
单层高 T/sub c/磁力计中多个 SQUID 排列的研究
DOI：
10.1109/77.783729
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发表时间：
1999
影响因子：
1.8
通讯作者：
H. Meyer
中科院分区：
文献类型：
--
作者：
V. Schultze;V. Zakosarenko;R. IJsselsteijn;J. Ramos;H. Meyer
研究了双晶衬底上的单层高T/sub c/ dc SQUID传感器。特别注意实现大的通量-电压传递函数，以确保SQUID电子器件的稳定操作，并且即使在干扰环境中也能获得低通量噪声。测试了30/spl deg/双晶体上的约瑟夫森结以及亚/spl μ/m结和24/spl deg/双晶体。通过sub-/spl μ/m图案化实现的陡峭边缘增加了超导结构对大的外部场的电阻。大通量-电压传递函数的设计集中在多个de SQUID装置上。对于直接耦合拾波回路的磁强计，三结SQUID与标准的两结SQUID相比没有优势，但两个普通直流SQUID的串联连接却有优势。尽管对于具有电感耦合拾波回路的磁力计，使用了串联的20个SQUID，但是由于各个SQUID的临界电流和电感的差异，对磁通-电压传递系数的影响很差。采用电感耦合单层拾波线圈的磁强计灵敏度远小于直接耦合的磁强计灵敏度。对于后者，形成为常规方形垫圈的拾取环与开槽方形垫圈相比显示出更好的结果。
Single layer high T/sub c/ dc SQUID sensors on bicrystal substrates were investigated. Special attention was paid to achieve a large flux-to-voltage transfer function in order to ensure stable operation of the SQUID electronics and to get low flux noise even in disturbed environment. Josephson junctions on 30/spl deg/ bicrystal were tested as well as sub-/spl mu/m junctions an 24/spl deg/ bicrystals. The steep edges achieved by sub-/spl mu/m patterning increased the resistance of the superconducting structures against large external fields. The design for large flux-to-voltage transfer functions focused on multiple de SQUID arrangements. For magnetometers with a directly coupled pickup-loop three junction SQUIDs show no advantage compared to standard two junction SQUIDs, but the series connection of two ordinary dc SQUIDs does. Although for magnetometers with inductively coupled pickup-loop twenty SQUIDs in series were used the effect on the flux-to-voltage transfer coefficient was poor, due to differences in the critical current and inductance of individual SQUIDs. The sensitivity of the whole magnetometer achieved with inductively coupled single layer pickup-loops is much smaller than with directly coupled ones. For the latter a pickup-loop formed as a conventional square washer shows better results compared to a slotted square.