Superconductivity of In5Bi3

Measurements of magnetic properties of superconducting In5Bi3 are reported. The single-crystal samples exhibit almost reversible magnetization curves and have resistivity ratios between 33 and 75. The results of the measurements in the superconducting state together with those of additional galvanomagnetic measurements allow estimates of some electronic constants of In5Bi3. The electron mean-free paths calculated in this way are about 20 times longer than the coherence length, i.e., the pure limit is approached very closely. This leads to the conclusion that In5Bi3 is an intrinsic type-II superconductor with a Ginzburg-Landau parameter k = 2.25 +/- 0.05. The transition temperature is 4.16 +/- 0.01 K and the thermodynamic critical field at T = 0 is 340 +/- 5 Oe. A comparison of the temperature-dependent constants k(1) and k(2) with the predictions of the theory for the pure limit shows deviations up to 8 % for k(1). For k(2) the agreement is good.