ISSN:
1434-6036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Niobium films on sapphire were reacted in tin-vapour to Nb∼3Sn with resistance ratiosR(297 K)/R(18.3 K) up to 6 and resistively measured superconducting transition temperaturesT c up to 17.93 K. The composition Nb3+z Sn1−z H x of electrolytically hydrogenated samples was determined depth dependent by Rutherford backscattering of 30 MeV32S and simultaneous detection of recoiled protons. Considerable concentration gradients in the thin layers (≈0.27 μm) were detected. The increase of resistivity ϱ with hydrogen content and the change in the temperature dependence of ϱ is analyzed. A correlation betweenT c and ρ0=ρ is found: An increase of ΔT c =0.2 K at ρ0≈25μΩcm andx≈0.03 is followed by a drastic decrease toT c 〈1.1 K at ρ0≈80μΩcm andx≈1. TheT c vs. ρ0 andT c vs. ϱ(T) characteristic correlations are different from “universal” irradiation or preparation induced correlations. The discrepancies can be interpreted by a stiffening of phonon modes and a band-shifting caused by the hydrogen.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01307318
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