Interplay of Coherence Length, Vortex Dynamics, and Penetration Depth in High-Entropy Alloy Nb₃(Al,Sn,Ge,Ga,Si) Superconductors

High-entropy alloy (HEA) superconductors exhibit unique vortex matter properties due to intrinsic disorder. We present a combined experimental and theoretical study of A15-type Nb₃(Al,Sn,Ge,Ga,Si), demonstrating that configurational entropy: Shortens coherence length (ξ ≈ 5 nm vs. 8 nm in Nb₃Sn) via enhanced scattering. Increases penetration depth (λ ≈ 250 nm) while maintaining λ/ξ ≈ 50 (Type-II behavior). Introduces anisotropic vortex pinning (𝐹𝑝 ≈ 10⁹ N/m³) through 𝐸₁* ≈ 0.02–0.04 energy landscapes.These findings establish HEAs as a platform to engineer superconductivity through entropy-mediated disorder. Lay Abstract:Scientists have discovered that mixing five elements equally in a niobium-based superconductor creates beneficial "disorder," enabling it to withstand stronger magnetic fields. This study shows how this chaos at the atomic level: Makes electrons pair over shorter distances. Allows magnetic fields to penetrate deeper. Locks magnetic vortices in place more effectively.The results could lead to better magnets for MRI machines and fusion reactors.