100 incredible years of physics – materials science
IOP member Clara Barker is a materials scientist managing the Centre for Applied Superconductivity at the University of Oxford. Her position allows her to pursue her passion of playing with materials and techniques in order to find new higher temperature superconductors, new types of thin films, and better ways to make them. But the journey to her current role has been littered with adversity. As a transgender woman starting her career, she hid her true identity for many years in often openly sexist and homophobic work environments. Eventually it came to the point where she felt she either had to keep her true identity private for the rest of her career, or transition and quit science altogether.
But then she attended a talk in Manchester by former IOP President Jocelyn Bell Burnell: “It was one of the first science talks that I saw that talked to me on a more personal level,” Barker says. “It was really amazing to hear her story about the adversity she’s faced, and how she’s overcome it.” Barker highlights the way this talk resonated with her as the start of a long journey to accepting her true self – culminating in applying for a role at Oxford’s Department of Materials, under her new name. She has not looked back since.
In 2018, Bell Burnell won one of the most lucrative prizes in science: the £2.3m Special Breakthrough Prize in Fundamental Physics. She donated the entire prize to the IOP to set up a fund to help people currently under-represented in physics, including students from ethnic minorities and LGBT students, to study at PhD level.
Her motivation to do this stemmed from her own experiences of being subjected to many prejudices as a female astrophysicist and her belief that the discipline will benefit from increased diversity at the PhD level. Echoes of Bell Burnell’s struggles can be heard in stories of the careers of many female scientists over the past 100 years. Yet unlike most other disciplines, materials science has a long history of fostering leading female physicists – at least in the subfield of crystallography.
Pioneered in 1913 by father and son team, William Henry Bragg (IOP President 1925–27) and William Lawrence Bragg (IOP President 1939–43), crystallography is a technique whereby X-rays are shone through crystals of a solid material. The resulting scatter of radiation is recorded to decipher the material’s crystal structure, which governs most physical properties of matter.
“You can’t underestimate just how important that early understanding from the Braggs was, and then how that’s been applied going forward,” says Barker. “I used crystallography yesterday and the day before that and the day before that – it’s the workhorse of what I do.”
After World War I, the Braggs actively encouraged women into science. Eleven of the elder Bragg’s 18 PhD students were women, one of which being Kathleen Lonsdale, who went on to be one of the first two women elected a Fellow of the Royal Society, first woman tenured professor at University College London, first woman president of the International Union of Crystallography, and first woman president of the British Association for the Advancement of Science.
Other lauded female scientists with strong links to the Braggs include Helen Megaw, Dorothy Hodgkin and Rosalind Franklin, as Barker further illuminates: “Lawrence Bragg worked on haemoglobin and that continued into the work that allowed Rosalind Franklin, James Watson, Francis Crick, and Maurice Wilkins to discover the double helix structure of DNA.”
A discipline in its own right
These crystallography founders were certainly conducting materials science research both during and after World War II. And more generally, the War effort had accelerated the development and mass production of a range of new materials, including plastics to replace scarce traditional materials like metal. However, the discipline was not recognised as a scientific subject until the US government realised that materials were the limiting factor for advances in space and military technology during the Cold War. Barker also highlights a more practical reason: “Originally you had metallurgy departments and ceramics departments, but because they were using the same manufacturing process, there was a certain point where it just made sense for people to be looking at materials together.” As a result, Northwestern University instituted a dedicated department in 1955, quickly followed by Barker’s Oxford in 1957 and other universities around the world. Materials science was finally on the scientific map.
Barker points out two other key moments in history that brought materials science to the fore. The first was the Information Age – arguably beginning in the late 1950s when Egyptian Bell Labs engineer, Mohamed Atalla, built a silicon transistor that would become the basic building block of all modern electronics: “The need to make computers and mobile phones smaller, faster, more powerful is probably what’s pushed materials science in terms of developing smaller, lighter materials that are able to deal with these complex calculations.”
The Information Age also added an armoury of new technology to the materials scientists’ toolbox. The power of computers was wielded to solve complex crystallographic calculations, and it automated crystallography experiments allowing researchers to design more accurate and powerful techniques. For example, crystallographer Ada Yonath used powerful synchrotron X-rays to help determine the structure of the ribosome – a complex particle responsible for producing all proteins in living cells – and the way antibiotics disrupt it. This insight will help to tackle the growing resistance of bacteria to antibiotics.
Running parallel with advances in computing and crystallography has been the development of the laser. From 1960 onwards, lasers slowly became ubiquitous, giving us the light-emitting diodes found in DVD players and smartphones, fibre-optic communication that has become the backbone of global connectivity, and confocal microscopy – a key tool in materials science. The latter is but one in a long list of ultra-sensitive spectroscopy and microscopy techniques that today allow researchers to delve even deeper into a material’s composition.
Rise of the wonder material
Barker’s second key moment was the isolation and discovery of graphene’s remarkable properties in 2004 by UK-based Russian physicists – and IOP Honorary Fellows – Andre Geim and Konstantin Novoselov, and their subsequent 2010 Nobel Prize in Physics. “All of a sudden with the Nobel Prize, people were talking about materials science,” she says. “I think it’s really grown awareness.”
“I love the concept that they had this Friday afternoon experiment where they were just playing around with some graphite – I mean, they were just pulling off layers using tape,” she adds. “For me, that’s the really interesting thing, as it shows you can be just trying new things, almost playing around, and something completely novel comes up. That’s really important for inspiring future scientists.”
Graphene is a supermaterial of almost limitless potential. It is a 2D material, no thicker than the width of an atom. Already graphene products provide clearer audio in earphones, slow wear in car tyres and offer lightweight strength in sports equipment. Continuing research at the National Graphene Institute in Manchester, and through the €1bn EU Graphene Flagship initiative, is expected to unlock thousands more uses for the wonder material.
What’s more, a huge family of other 2D materials have since been discovered, with equally interesting properties. And each can be combined and stacked in different ways, forming new shapes – like tubes, ribbons, wires and balls – at the nanoscale, offering an almost limitless number of potential applications.
Materials from and for all society
When we look back 100 years, the range of materials used in products was very limited, consisting of natural materials, a limited number of uncomplicated metals and a few plastics and ceramics. In stark contrast, researchers today can design new materials from scratch and modify existing ones in a myriad of ways. This ability marks out materials science as the key to solving some of the world’s greatest challenges.
Barker lists improved batteries and fuel cells for electric cars and a host of other portable devices; superconductors for efficient electricity generation and faster computing; materials to withstand the intense environment of future nuclear fusion reactors; and a multitude of materials for medical applications as some of the most intensely studied areas of materials science research today.
In essence, these are all hot topics in materials science because they aim to improve life on our planet. But to realise them, Barker says that more needs to be done to widen participation in materials science and the wider scientific community. “If people know that they’re welcome, it will inspire them to go into a scientific field. That’s going to bring forward our biggest breakthroughs and enrich our problem solving, because we’ll have the people to do it.”
|William Bragg knighted for inventing crystallography with his son Lawrence||1920||Prohibition begins in the USA|
|The plastic PET – now widely used for bottles – discovered in UK||1941||The US joins World War II after Japan attacks Pearl Harbor|
|First photovoltaic solar cell unveiled by Bell Labs||1954||Roger Bannister achieves the first sub 4-minute mile run|
|The MOSFET signals the dawn of the Silicon Age||1959||Dalai Lama is forced to flee Tibet|
|Semiconductor lasers and LEDs – the basis for modern telecommunications – developed||1962||The Beatles release their first single: ‘Love me do’|
|RCA announces they have built the first liquid crystal display||1968||Martin Luther King Jnr assassinated|
|Scanning tunnelling microscope invented||1981||Scientists identify the Aids virus|
|First high-temperature superconductor discovered||1986||Russian leader Mikhail Gorbachev introduces ‘perestroika’ (restructuring) and ‘glasnost’ (openness)|
|Sony sells the first commercial rechargeable Li-ion battery||1991||The decade-long Yugoslav Wars begin, eventually leading to the breakup of the Yugoslav state|
|Graphene’s remarkable properties exposed||2004||Facebook launches for students from Harvard|
|The ‘queen of carbon science’ Mildred Dresselhaus is awarded the Presidential Medal of Freedom||2014||The largest Ebola outbreak in history strikes West Africa|