its high Sommerfeld coefficient of the order of 100 mJ/(mol K 2), which signals strong
electronic correlations. A new generation of high quality samples of YFe 2 Ge 2 show
superconducting transition anomalies below 1.8 K in thermodynamic, magnetic, and
transport measurements, establishing that superconductivity is intrinsic in this layered iron
compound outside the known superconducting iron pnictide or chalcogenide families. The …