Influence of trapped magnetic field of Sn-Pb solders on electrical resistivity measurement: an example of superconducting transition of Sn

Soldering has been used in various scientific and industry cases for long time. In researches of materials science and condensed matter physics, researchers have used soldering to fabricate electrical terminals for characterization of electric properties. In a recent study, anomalously huge magnetic flux trapping has been observed in the Sn-Pb solders after field cooling or high-field experience at low temperatures lower than superconducting transition temperature (T < Tc = 7.2 K) of the solders. In this letter, we tested the affection of the flux-trapped states of solders (Sn60-Pb40) on superconducting properties of a Sn wire (Tc = 3.7 K) because solders have been generally used for investigation of superconducting samples. The temperature dependence of electrical resistivity ({ho}-T) at H = 0 Oe after zero-field cooling (ZFC) showed normal sharp superconducting transition at T = 3.7 K. In contrast, the {ho}-T after field cooling (FC) showed lowered Tcs and broadening of the superconducting transition. The difference in {ho}-T between ZFC and FC states evidences the critical affection of the flux-trapped states of Sn-Pb solders on superconducting states. We propose that, in electrical measurements where magnetic field of several hundred Oe, the field experience should be seriously considered in the experiments.