Investigation of a spin-resonance in unconventional superconductor YFe2Ge2

In the layered iron-based superconductor YFe2Ge2, a high Sommerfeld ratio of order 100 mJ/mol K^2 and a T^3/2 temperature dependence of the electrical resistivity at low temperature indicate strong electronic correlations and point towards an unconventional pairing state. Theoretical proposals for the superconducting state include s+- or triplet pair wavefunctions and there are striking structural and electronic similarities to some of the iron pnictide superconductors. Investigation of magnetic excitations in the superconducting state by inelastic neutron scattering experiments has been held back by the lack of high quality, bulk superconducting samples. We are now able to grow single crystals with a bulk Tc of about 1.1K and RRR > 300. Inelastic neutron measurements of the superconducting state in these crystals will provide a step forward in understanding the pairing state in YFe2Ge2.