Nanoengineered superconductors

Materials World magazine
1 Dec 2009

Artificially nanoengineered pinning centres have been introduced to high temperature superconducting (HTS) thin films to increase their critical current density by up to three times that of the standard 1.5 Tesla.

This work, conducted by researchers from the Universities of Birmingham and Cambridge, both in the UK, could lead to novel magnetic levitation devices and power storage systems.

‘Controlled nanoengineering of superconducting materials, such as thin films, wires and bulk, will enhance flux pinning, a phenomenon that prevents the creation of “pseudo-resistance”, which reduces the material’s [superconducting] performance,’ explains Dr Adrian Crisan of the University of Birmingham.

Increased flux pinning is achieved by embedding silver nanoparticles into the grains of the superconducting matrix. The reaction creates extended cilumnar defects, which ‘pin down’ a vortex within the material. ‘In practical terms, this enables you to increase the maximum current you can pass through a superconducting wire or cable without causing dissipation, increasing power,’ says Crisan.

A substrate decoration technique introduces these centres into HTS thin films. This consists of growing nanodots on a substrate prior to the deposition of the superconducting thin film using an excimer laser.

‘Our next goal is to develop different types of nanotechnology pinning centres using different materials and transfer our knowledge to industry to develop real world HTS systems,’ adds Crisan.