Ultra-high sensitivity scanning SQUID microscopy with dispersive readout

• Applicant: Professor Dr. Hendrik Bluhm
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 256185976

• Final Report Year: 2018

Final Report Abstract

During the funding period, we developed a novel type of SQUID microscope based on dispersive readout. As anticipated, this approach resulted in significant improvements in sensitivity and bandwidth, thus overcoming fundamental limitations of traditional DC-SQUIDs regarding these important figures of merit. The realization of the project suffered however a significant slow-down due to the delays in the sensors’ supply and to the engineering challenges related to the integration of the dispersive read-out into the scanning microscope. Because of these delays, we were unable to address the scientific tasks of the project (Tasks A3 and A4) within the funding period. Despite some room left for further optimization, the microscope in now active and running, and it at the base of a collaboration with the group of Prof. Yoichi Ando on the characterization of superconducting rings that incorporates Josephson junctions based on topological insulators.

Publications

• A micro-SQUID with dispersive readout for magnetic scanning microscopy, Appl. Phys. Lett. 112, 252601 (2018)
  F. Foroughi, J.-M. Mol, T. Müller, J. Kirtley, K.A. Moler, and H. Bluhm