Type-I superconductivity in YbSb2 single crystals
Zhao, Liang L.
We present evidence of type-I superconductivity in YbSb2 single crystals from dc and ac magnetization, heat capacity, and resistivity measurements. The critical temperature and critical field are determined to be Tc ≈ 1.3 K and Hc ≈ 55 Oe. A small Ginzburg-Landau parameter κ = 0.05, together with typical magnetization isotherms of type-I superconductors, small critical field values, a strong differential paramagnetic effect signal, and a fieldinduced change from second- to first-order phase transition, confirms the type-I nature of the superconductivity in YbSb2. A possible second superconducting state is observed in the radio-frequency susceptibility measurements, with T (2) c ≈ 0.41 K and H(2) c ≈ 430 Oe.