Reentrance of the induced diamagnetism in gold-niobium proximity cylinders

Original · EN

We discuss the magnetic response of gold-niobium proximity cylinders in the temperature range 100 μK<T<9 K. The temperature dependence of the susceptibility in the diamagnetic regime is described well by the quasiclassical Eilenberger theory including an elastic mean-free path l. In the mesoscopic regime, the temperature dependence of the reentrant paramagnetic susceptibility χₚara(T) ∝ [-L/3ξᵈₙ(T)] is governed by the dirty limit coherence length ξᵈₙ(T)=√1/3ξₙ lₙ, with ξₙ the clean limit coherence length obtained from breakdown field measurements and lₙ the measured mean-free path in the gold layer. At T=100 μK, χₚara compensates about 1/5 of the induced diamagnetic susceptibility in gold.