Physikalisch-Technische Bundesanstalt

Tasks

We focuse our activities on the research and current developments of programmable voltage standards based on the Josephson effects. These programmable Josephson voltage standards have increasingly gained in importance in recent years, after conventional 1-V and 10-V Josephson voltage standards are successfully operated in all important national institutes and some company laboratories world-wide. In contrast to conventional voltage standards consisting of underdamped Josephson junctions, programmable voltage standards consist of overdamped Josephson junctions. Overdamped Josephson junctions are realised e.g. using a Superconductor/Insulator/Normal conductor/Insulator/Superconductor (SINIS) multilayer structure. They show a non-hysteretic current-voltage-characteristic, which remains single valued under microwave irradiation. 1-V arrays consisting of 8192 SINIS junctions divided into a binary sequence are successfully operated at PTB and some European national institutes. Additionally, first 10 V arrays consisting of about 70000 SINIS junctions were realised.

Main tasks are:

• Development, fabrication, and investigation of binary divided Josephson series arrays for programmable voltage standards
  
  
• Development of a pulse-driven AC Josephson voltage standard including fabrication and investigation of suitable series arrays (JAWS)
  
  
• Investigation of different materials for optimized Josephson junctions

The arrays are fabricated using the technology of the department in the Clean Room Centre of PTB. Measurements and applications are performed in close co-operation with department 2.6 and the working group 2.63 Josephson Effect, Voltage. The AC Josephson voltage standards are partly developed within the framework of national and international projects, especially within the framework of the project JoSy (EMRP JRP T4.J03), the EUROMET project 756, and the project S-PULSE (support action within FP7) at present.

The research and development activities are additionally integrated into further national and international projects and co-operations (Project partners and co-operations).

Within the framework of the S-PULSE project, we organized the workshop "Applied Superconductor Electronics in Quantum Metrology" in May 2009.

We hosted the Workshop Kryoelektronische Bauelemente (Kryo 2008) in October 2008. Information of this workshop are collected at Kryo 2008 (in German), press release of PTB (in German) and the IEEE CSC European Superconductivity News Forum. 

Team

The Team in front of the Clean Room Centre of PTB. 

Contact