Postgraduate Seminar Series Thursday 21st February Room 564 5pm Small Angle Neutron scattering on the anisotropic superconductor CaC6. By Andrew Crichton Small-angle neutron scattering has been applied to study the vortex lattice in the intercalated graphite superconductor CaC6 Tc=11.3 K. Scattering from the vortex lattice is in the form of a ring, reflecting the absence of in-plane orientational order of the pyrolitic graphene planes. The temperature and field dependence of the scattered intensity allows the in-plane zero temperature value of the coherence length and the London penetration depth to be estimated. The orientation of the vortex lattice is fixed relative to the rotation axis of the crystal as predicted by anisotropic London theory. The Cataclysmic Variable GW Librae By Lieke van Spaandonk A Cataclysmic Variable (CV) is a binary star system where two stars orbit each other around their centre of mass. The primary is the more massive star of the system and will have evolved into a white dwarf (compact degenerate star), while the secondary is still a main sequence star (fusing hydrogen) and is transporting mass towards the primary. Due to friction this gas will expand to form an accretion disc around the white dwarf. At some point this disc will become unstable and go into outburst, brightening the system up to a few hundred times. GW Lib is such a system. The postgraduate seminar series is a series of informal talks run by postgraduates for postgraduates. All postgraduates are welcome and refreshments are always provided!