Measurement of the spatial sensitivity of miniature SQUIDs using magnetic-tipped STM
Measurement of the spatial sensitivity of miniature SQUIDs using magnetic-tipped STM
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DOI：
10.1088/0953-2048/16/12/054
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发表时间：
2003-12-01
影响因子：
3.6
通讯作者：
Macfarlane, JC
中科院分区：
文献类型：
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作者：
Josephs-Franks, P;Hao, L;Macfarlane, JC
大面积超导量子干涉器件(SQUD)被认为是磁通量的终极传感器。通过减小SQUID环的大小，该设备的能量灵敏度可以提高到接近量子限制的操作，同时还使其对外部磁场噪声不那么敏感，并改善其与环内任何纳米级磁性粒子的耦合。这使得它成为包括单分子在内的磁性粒子的理想纳米传感器。然而，重要的是优化放置在SQUID中的任何磁性纳米粒子与SQUID本身之间的耦合，以实现最大的自旋检测灵敏度。我们已经对放置在SQUID装置内不同位置的磁粒子的预期SQUID响应进行了一些初步计算，并使用扫描隧道显微镜(STM)中的磁尖，我们能够产生SQUID灵敏度的空间地图。给出了一个直径为3微米的环形鱿鱼的初步结果，以验证该方法。
Large area superconducting quantum interference devices (SQUIDS) are known to be ultimate sensors of magnetic flux. By diminishing the size of a SQUID loop, the energy sensitivity of the device can be increased to near quantum-limited operation whilst also making it less sensitive to external magnetic field noise and improving its coupling to any nano-scale magnetic particle within the loop. This makes it an ideal nano-sensor for magnetic particles including single molecules. It is, however, important to optimize the coupling between any magnetic nano-particle placed within the SQUID and the SQUID itself in order to achieve maximum sensitivity for the spin detection. We have made some preliminary calculations of the expected SQUID response to a magnetic particle placed at different locations within the SQUID device, and using a magnetic tip in a scanning tunnelling microscope (STM) we are able to produce a spatial map of the SQUID sensitivity. Initial results on a 3 mum diameter loop SQUID are presented to demonstrate this method.