Experimental Study of the Proximity Effect in Thin-Film Heterostructures with the Superconducting Lead Layerof Variable Thickness

A systematic study is performed of the superconductor/normal metal, superconductor/antiferromagnet, and superconductor/ferromagnet proximity effects in structures with superconducting lead layers of variable thickness. It is shown that temperature T_s of the superconducting transition in these systems behaves differently when the superconducting layer is thinned. In superconductor/antiferromagnet structures, T_s changes negligibly within the investigated range of lead layer thickness. Ratio RRR (R_{300 K}/R_{10 K}) of electrical resistance falls notably as the lead layer thins, which could indicate a growing contribution from surface defects. The width of superconducting transitions grows as the lead layer thins, testifying to size effects.