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Jeudi 20 Septembre, 16h
Amphi Howleck, Esc C, 1ème etage
Quantum Oscillations in the Ferromagnetic Superconductor URhGe
E. Yelland
University of Edinburgh and University of St Andrews
URhGe orders ferromagnetically below 9.5K and coexisting superconductivity develops in the cleanest samples at 300mK. For magnetic fields applied along the b-axis, superconductivity is first destroyed at a critical field 2T but a second superconducting phase forms at higher fields 8 < B < 12T. I discuss the role of a small, strongly magnetic field-dependent Fermi surface pocket of heavy quasiparticles in driving the re-entrant superconductivity [Yelland et al., Nat. Phys. 7, 890 (2011)] and how this affects our view of the magnetic and superconducting phase diagram. New quantum oscillation results have revealed other sections of the Fermi surface including quasiparticles of 100 electron masses. I compare the experimental Fermi surface with that obtained from electronic structure calculations and discuss the possible role of symmetry-related degeneracies in the electronic structure.