You’ve got to have curiosity – A Fellow Perspective: Susie Speller
From the future of energy to the pressures of student life, Dean of St Catherine’s, Fellow, and Professor of Materials Science, Susie Speller reflects on how curiosity, community and confidence shape both scientific discovery and the Catz experience.
Susie still remembers the moment everything changed. At 15, hoping for a placement in forensic science and finding that forensic labs didn’t take work experience students, she instead spent a week in a materials laboratory in Cambridge, exploring the microscopic structure of everything from violin wood to natural fibres. “I just loved it. I spent the week playing with the microscope, looking at all sorts of things, wood, strings, anything we could find, and that was it.”
That moment of curiosity became a career, one now focused on some of the most complex scientific challenges of our time. As Professor of Materials Science at Oxford, Susie leads research into superconductors: materials that, when cooled to extremely low temperatures, can carry electrical current with no resistance at all. It’s a property that already underpins technologies such as MRI scanners, where electrical currents can flow indefinitely without power loss, but its implications reach much further.
Superconductors sit at the heart of the future of energy. In fusion reactors, they generate the powerful magnetic fields needed to contain plasma at temperatures of over 150 million degrees, while operating just metres away at around minus 200 degrees. “You’ve got this incredibly hot plasma, and then right next to it your superconductors are extremely cold, and in some designs there’s only a metre or two between them. It’s pretty amazing that you can do that.”
For Susie, the real excitement lies in what comes next. Advances in high-temperature superconducting materials, once too expensive for widespread use, are beginning to unlock applications at scale, from fusion energy to power transmission and beyond. “It’s been a bit of a chicken-and-egg problem. You need demand to bring the cost down, but you need the cost to come down before people can use it. What’s exciting now is that fusion really needs this material, and that’s starting to drive the scale-up.”
Fusion, in particular, could be the catalyst, not just for clean energy, but for unlocking wider technological change. “It’s not just about fusion. It’s about everything that follows from that, all the other applications we’ve known about for years but haven’t been able to use.”
That instinct, to look ahead and understand where research can have real impact, has shaped Susie’s career. More than a decade ago, she made a deliberate decision to focus on how superconducting materials behave in the extreme conditions of fusion environments, at a time when few others were working in the area. “I realised this was going to be really important, and that not many people were looking at it. So I made a conscious decision to move into that space, and it’s become a really hot topic.”
It’s a mindset she now passes on to students. In the Materials Science Department, here at Oxford, undergraduates are immersed in research early on, learning not just technical knowledge but how to think, collaborate and work independently. “First of all, you’ve got to have curiosity, you’ve got to really want to understand what’s going on. But it’s also about how you work: being organised, being proactive, listening, working with other people. Nobody can do this on their own.”
Alongside her research and teaching, Susie is also Dean of St Catz, a role that brings her into close contact with the realities of student life. “Being a student in Oxford is a fantastic opportunity, but it also comes with challenges. The terms are short, the pressure is intense, and students are often a long way from home, trying to make the most of everything at once.” Supporting students through that, whether by guiding them to the right help or simply listening, is, for Susie, central to the College’s role. “To do well academically, they need to be well in themselves. Sometimes it’s about helping them find the right support, and sometimes it’s just about being there and listening.”
Her connection to Catz spans more than two decades, evolving from teaching into a deeper involvement in the life and leadership of the College. “The community is just fantastic. You can have those intellectual conversations, but you can also just talk, unwind, reflect, and support each other. It’s a ‘space’ away from the department, and that really matters.”
That sense of belonging is something she experienced as a student too, and it has stayed with her. “I’ve always felt that I can be myself here. At school, I sometimes felt like I had to pretend to be someone I wasn’t, but at Oxford there’s such a diversity of people that you can just be who you are. And over time, that’s built confidence, I’m much more confident than I ever thought I would be.”
It’s a reminder that, alongside academic achievement, Oxford is also a place where people grow, not just intellectually, but personally. Outside the lab and the College, Susie’s work returns, in an unexpected way, to where it all began. A keen maker, she spends her spare time crafting violins and cellos, a practice that echoes those early encounters with materials, structure and form. From fusion energy to fine craftsmanship, her work is defined by the same instinct that first drew her in: curiosity, and the belief that understanding how things are made can help shape what comes next.
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Find out more about Susie, here.