Marsden grant will explore superconductivity
Robinson scientist Dr James Storey has been awarded a Marsden Fast-Start grant to study the still-unknown origin of high temperature superconductivity.
The research proposal entitled Putting the Heat on High-Temperature Superconductors will develop and use several new techniques to explore the electronic effects that give rise to high temperature superconductivity (HTS), which Dr Storey says remain “tantalisingly out of reach”.
“It’s a nearly 30-year old problem that I can’t hope to solve on a Fast-Start, but my goal is to make a strategic advance towards a better understanding of the phenomenon,” he says.
Dr Storey will use differential heat capacity and thermoelectric power measurements to probe the electronic structures of a series of HTS materials.
“Measuring how much heat you have to apply to a superconductor to raise its temperature sounds simple, but the experiment tells you a lot of information about what the electrons are doing.”
With his collaborators at the University of Cambridge, Dr Storey plans to perform measurements on single-crystal samples, rather than the randomly orientated polycrystalline materials used previously.
“Single crystals are typically only a few millimetres long but produce data that is free of unwanted artefacts arising from, for example, grain boundaries. They are becoming the standard for measurement.”
As the size of the sample decreases, however, greater sensitivity is required from the instruments used to the measure the changing temperature.
“Our collaborators in Cambridge have developed a special differential probe that I will use to do the measurements. We will be the first group to do differential specific heat measurement on single crystals.”
Dr Storey studied for his PhD in the fundamental physics of superconductivity at Victoria University of Wellington with Professor Jeff Tallon. He has continued to research in the area at the Robinson Research Institute.
“Superconductivity in conventional low temperature superconductors is known to be caused by atomic vibrations. But in HTS there are so many things going on that it’s hard to pin down one excitation as the smoking gun. My research will involve untangling a bunch of different effects.“A theoretical understanding of high temperature superconductivity is potentially very powerful—it would enable us to calculate a new material’s superconducting transition temperature or predict a superconducting material that hasn’t yet been found.”