基于聚焦氦离子束加工工艺的高温超导SQUID磁强计的研发

基于制备高温超导约瑟夫森结的新方法，以高温超导体的金属绝缘体相变为基础，以铜氧化物高温超导电子器件为对象，采用器件仿真、先进制备和噪声机制相结合的方法，利用聚集氦离子束加工工艺和电磁电路仿真的关键技术，研发低噪声、高灵敏度高温超导SQUID磁强计，阐明聚焦氦离子束调控高温超导体超导电性的微观机制及高温超导SQUID磁强计的噪声机制，解决高温超导SQUID磁强计难以可控重复制备的难题，探索超导SQUID磁强计的本征噪声与环境、衬底、薄膜和器件参数等物理量的关联规律，提高基于聚焦氦离子束加工工艺的超导SQUID磁强计的磁场探测灵敏度，实现本征磁场噪声小于200fT/sqrt(Hz)的性能指标，为新一代生物磁和地磁勘探技术提供关键的应用基础。

A new method to reproducibly fabricate high-quality high temperature superconductor (HTS) Josephson junctions has been developed in recent years, which is based on the metal insulator transition of HTS materials under the irradiation of a high-energy focused helium ion beam (He-FIB). Low-noise and high-sensitive HTS superconducting quantum interference device (SQUID) magnetometers will be fabricated with a He-FIB and the microscopic mechanism of the phase transition under the He-FIB as well as the noise mechanism in HTS SQUID magnetometers will be systematically investigated. The key technologies engaged in this project are He-FIB, electromagnetic simulation and circuit simulation. This project is to address the problem that HTS SQUID magnetometers are highly difficult to be reproducibly fabricated. We plan to improve the magnetic field sensitivity of HTS SQUID magnetometer for bio-medicine and geophysics applications, on the basis of experiment results and the quantitatively understanding of the relations between the intrinsic noise with the environment, substrate, film and device parameters, and to realize a SQUID magnetometer with intrinsic field noise less than 200fT/sqrt(Hz).