For the design of FCC-hh superconducting magnets an increase of the high field critical currents in

commercial Nb3Sn wires by about 50 % is required. Feasibility to reach this target was recently

demonstrated by neutron irradiation. The underlying mechanisms are to be clarified and realized

in industrial processes.

The scope of this project is to establish the correlation between the microstructure, the local

superconducting properties and the resulting macroscopic performance of superconductors for

magnets. This will be achieved by micro- and nanostructural examinations (grain geometry, local

texture, grain boundary morphology, compositional gradients) of the material structure

(contribution of Universitäre Service-Einrichtung für Transmissions-Elektronenmikroskopie

USTEM) and measurements of the superconducting properties by transport, magnetometry, and

scanning probe experiments (contribution of Atominstitut ATI).