Superconductors – substances which conduct electricity with no loss of energy – have been known about for nearly a century. But in the mid-1980s, a new material was found which showed superconductivity at much higher temperatures than had previously been seen. The detailed crystal structure of the first ‘high-temperature superconductor’, YBa2Cu3O7-x, was successfully determined at ISIS in 1986 using neutron diffraction. Such studies are essential to understand how superconductors work and to try to develop them for technological applications.
WIF David et al., Nature (1987) 327 310-312.
C60 crystal structure
The crystal structure of C60 ‘buckyballs’, the novel football-shaped form of carbon, was determined at ISIS in the early 1990s by diffraction experiments. A very large number of molecules based on C60 have been produced since its discovery, and knowledge of their structures is essential to understand their properties.
WIF David et al., Nature (1991) 353 147-149; Europhys.Lett. 18 (1992) 219.
Superconductivity in C60 materials
C60 molecules doped with alkali metals such as potassium or rubidium can become superconducting at low temperatures. Important for this behaviour is how the molecules vibrate, and an understanding of this can help explain how the superconductivity in these materials works. Neutron measurements of the vibrational spectrum of doped C60 material have provided important information.
K Prassides et al., Nature 354 (1991) 462.
Surfactant behaviour at interfaces
The behaviour of complex mixtures, for example formulations such as shower gels and shampoos, can be very different at interfaces compared with that seen in the bulk. Neutron reflectivity provides a powerful method for exploring interfacial behaviour, yielding unrivalled structural information at the Ångstrom scale – for example enabling the structure of adsorbed surfactants to be determined at the air-water interface.