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Advertising division: PGI-5 - Microstructure Research
Reference number: D036/2018, Physics

Master thesis: Scanning probe microscopy using nanoscale superconducting quantum interference devices (nano-SQUIDs)

Spatial imaging of magnetic fields by scanning superconducting quantum interference devices (SQUIDs) is a powerful technique for imaging of magnetic fields produced by currents in electronic devices and by magnetic nanoparticles, evaluation of defects in materials and magnetization states of spintronics devices, etc. Due to their high sensitivity and negligible reverse effect on the investigated object, SQUIDs can be potentially implemented for non-destructive readout of the final states of superconducting flux qubits after their protection by sufficiently high potential barriers. Nanometer-sized SQUIDs (nano-SQUIDs) demonstrated the unprecedented spin sensitivity and spatial resolution (Anahory et al., Nano Lett. 14, 6481, 2014). Implementation of electrically tunable multi-terminal nanoSQUID’s configuration (Uri et al., Nano Lett. 16, 6910, 2016) provided the optimal flux bias conditions by direct injection of the flux modulation and feedback current into the SQUID loop.

It is planned to develop a nano-SQUID measurement system that would be used at PGI-5 and ER-C to study magnetic effects that are occurring in small samples on a nanometer scale as a technique complementary to the electron holography measurements that are currently performed at ER-C.

The work is embedded in the international team at the Institute for Microstructure Research (PGI-5) and Ernst-Ruska-Centre. The candidate will operate the available SQUID microscope system that is intended for investigation of magnetic fields of room temperature objects and participate in development of a new nano-SQUID microscope system based on low temperature high precision ultra large scan range piezo scanning stages of company “Attocube” and a nano-SQUID as a supersensitive detector of magnetic fields that are generated at liquid helium temperatures with submicrometer spatial resolution.

Depending on the actual progress of the project there will be different tasks related to development of electronics for low noise operation of nano-SQUIDs, construction and assembling of fine mechanical parts including the piezo scanning stages, cryogenics, vacuum technology, magnetic shielding, semiconducting and superconducting electronic components, system control and readout software, etc.

The nano-SQUID microscope system will be used for imaging of magnetic field of different nanoscale objects that are related to the rapidly evolving research fields of topological materials, spintronics, quantum computation and artificial intelligence.

Contact person:
Prof. Dr. Michael Faley
Forschungszentrum Jülich
Ernst Ruska-Centre for Electron microscopy