Field dependence of the superconductive penetration depth in In and diluteInBi alloys

We have studied the superconductive penetration depth λ(T,H) by mutual inductance at 75 kHz in small, single spheres of In and InBi (0.19, 0.395, and 0.60 at.%). The corresponding Ginzburg-Landau parameters κ(t=1) are 0.061, 0.155, 0.240, and 0.349, respectively. The temperature dependence of the penetration depth is equally well described by λ(t)=λ₀(1-t⁴)1/2 and λ(t)=λ₀^'ZBCS(t). Respective values of λ₀ are 395, 510, 630, and 685 ±{} 30 {}, while λ^'₀ is 275, 355, 440 and 480 ±{} 20 {}. The field dependence of λ was obtained at $t=0.983$ for fields up to the ideal superheating field Hₛₕ. At Hₛₕ, we find λ(Hₛₕ)λ(H=0)=1.46,1.44,1.46, and 1.53±0.05 respectively, confirming the previous measurements on Sn. In "weak" fields HHₛₕ we find λ(H)λ(0)1+α(HHₛₕ)², with α=0.08,0.16,0.18 and 0.19±0.08. We discuss in detail the agreement with theory, which is quite good.