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!