In search of the superconductor Holy Grail
So-called superconductors already exist, however at the moment even the so-called ‘high temperature superconductors’ need to be cooled to temperatures far below zero degrees Celsius in order to work, severely limiting their use.
The discovery of a superconducting material that is abundant in nature and could be used at higher temperatures cheaply and with relative ease ‘would really be the Holy Grail,’ Dr Sebastian said. ‘It would not just be an incremental advantage – it could lead to drastically different ways of sustainable living.’
If superconducting transmission cables became a reality, for example, more efficient transportation of power with no losses would help grids keep up with growing demand.
It would also open up exciting possibilities for renewable energy producers seeking ways to bring together small amounts of power from multiple generation sites efficiently and cost-effectively.
Makers of electrical vehicles and wind turbines could start using light, gearless motors and generators as the conductors wouldn’t lose power.
150 degrees Celsius below zero
‘High-temperature’, or ‘unconventional’, superconductivity was discovered over 25 years ago, but the copper oxide-based materials in question, while working at a higher temperature than previously known superconductors, still need to be cooled to about 150 degrees Celsius below zero to function.
Dr Sebastian, who was awarded a five-year grant from the European Research Council for her research project SUPERCONDUCTINGMOTT, wants to find out what it is about copper oxide-based materials that causes them to work as superconductors, hoping it will shed some light on other materials that may work at higher temperatures.
Scientists already know that superconductors perform the way they do because electrons pair up and therefore avoid any resistance. ‘The big question is "what is the glue?",’ Dr Sebastian said.
In an attempt to reveal what it was that produced the right conditions for those electrons to pair up, she is applying strong magnetic fields to copper oxide-based superconductors to destroy their superconducting properties.
That would allow her to identify what it is that makes something superconductive, and start looking for the same characteristics in other materials to see if they are also superconductive. ‘There are multiple theories at the moment and no consensus. Often the proof of a theory is if it is predictive,’ Dr Sebastian said.
Once she discovers which characteristics give the material its superconducting properties – and what different superconductive materials have in common – then that will help her formulate a ‘roadmap’ for the discovery of other superconductor materials.
‘Most often superconductors are found accidentally, through a sort of serendipity. I am actively looking for new families of superconductors and a roadmap of guiding principles that shows what they have in common,’ Dr Sebastian said.
Gender equality is good for science
Dr Sebastian believes her field would benefit from more diversity. ‘It’s very male-dominated but gender is just one issue. It’s very homogenous and there’s a large element of self-selection – people identifying with what they see good scientists being – very intense, narrowly focused and quite aggressively competitive. I would like it to be more collegial.’
She studied physics as an undergraduate and, wary of pursuing a career in a field she feared might be too narrowly focused and ‘geeky’, went on to do an MBA and work as a management consultant. However, she missed the discovery of research, so returned to physics with a PhD at Stanford University in the United States. ‘I still wasn’t sure about a career in research but I liked physics. It was only towards the end of my PhD that I started to understand what research was all about. Once you start finding new things, it’s almost like you can’t go back.’
In June 2013, Dr Sebastian was awarded a L’Oréal-UNESCO Women in Science fellowship and she believes strongly in the need to raise the visibility of women in science and ensure younger women are not put off by the perceptions of a poor work-life balance and highly competitive environment; not just for the sake of women but for the good of science too.
‘It’s extremely important to have role models, positive reinforcement and platforms for women,’ she said. ‘Science is missing out if it is focusing on just this one group of people. In a way it’s more important for science than it is for women.’
Dr Suchitra Sebastian, Department of Physics, Cavendish Laboratory, University of Cambridge
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