Rights: The University of Waikato Published 9 April 2010 Download

How do you make superconductive ceramic wire? How can you improve the electric current carrying capacity of the superconductive ceramic wire? These are just two of the problems that Dr Nick Strickland and his superconductor research team at IRL are investigating. Their focus is on changing the properties of the thin film of superconducting ceramic material present in the wire such that it can carry more electric current and, in particular, more current when a magnetic field is applied.

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Making these materials into a wire has been the great challenge of the last 20 years or so, and there are a number of approaches to do this. The one that is being adopted at the moment is to take a metal foil and then deposit a very thin film of a superconductor on top of the foil. So the film of superconductor is only 1 micron thick, so that is 1 thousandth of a millimetre, a very very thin layer, but this can conduct a very high current.

Our research concerns studying the properties of the thin film that is on top of this metal tape and trying to change the properties of the film so that it can carry more current and, in particular, more current when you apply a magnetic field. So related to the Meissner effect, when you apply a magnetic field, you can actually put less current through a superconductor before it becomes a non-superconductor. So there are certain things that you can do to the microstructure of the film to allow it to carry more current. Carrying more current can, for example, allow you to create a high-field electromagnet with less wire, with less windings. Therefore, it can be smaller and lighter. You could also create a transmission line with a much smaller cross-section.

All these things are desirable, making your devices as small as possible. It makes them cheaper and easier to cool.