"The purpose of this postdoctoral research project is to investigate the mechanism that leads to the high temperature superconductivity. In particular, this project is focused on performing a comprehensive study of fundamental electronic properties, in both the normal and superconducting states, of the recently discovered iron-pnictide superconductors. These systems have very interesting phase diagrams where the superconducting and magnetic properties dramatically change as a function of doping. The objectives are to understand further the normal state electronic structure, investigate the superconducting gap structure and determine the relationship between them across the phase diagram. To achieve these objectives three experimental techniques will be used providing complementary and consistent information on the same samples. Studies of the normal electronic structure will be performed using de Haas-van Alphen effect whereas the superconducting gap structure will be probed by magnetic penetration depth and angle resolved specific heat measurements. These experiments will be performed at temperatures down to the milikelvin regime and under magnetic fields up to 70T. Most part of the research will be carried out at the University of Bristol in the Correlated Electron Systems Group under the supervision of Professor Antony Carrington although the project involves collaborations with other recognized groups and international high magnetic field facilities such as the LNCMI in Toulouse."