Superconducting state in YSn₃ with a AuCu₃-type structure

In this paper, the superconducting properties of YSn3 are reported. YSn3 has a cubic AuCu3 -type structure with the space group Pm 3̄ m. Magnetic susceptibility, electrical resistivity, and specific-heat data showed that YSn3 is a superconductor with a superconducting transition temperature (Tc) of 7 K. The magnetization versus magnetic field (M-H) curve shows the typical type-II superconducting behavior. The estimated lower critical field Hc1 (0) and the upper critical field Hc2 (0) are about 90 Oe and 3000 Oe, respectively. The penetration depth λ (0) and coherence length ξ (0) are calculated to be approximately 270 nm and 66 nm, respectively, using the Ginzburg-Landau equations. The estimated Sommerfeld coefficient γN is 7.57mJ/mol K2. The normalized specific heat jump ΔC/ γN Tc is estimated to be about 2.19, which is higher than the value predicted by the BCS theory in the weak-coupling limit, i.e., ΔC/ γN Tc =1.43. This fact indicates that superconductivity in YSn3 exists in the strong-coupling regime. The difference between Tc of Ln X3 (X=family of 13 or 14 elements) compounds is discussed to compare their physical properties.