CONDENSED MATTER SEMINAR

Dr. Andrey Rogachev

University of Utah

“Non-additive effect of superconductivity suppression by

thickness reduction and

magnetic Gd impurities in amorphous MoGe Films”

The effect of magnetic Gd atoms on superconducting properties of amorphous Mo-Ge films with the thickness in the range 1-50 nm was systematically studied. The critical temperature,Tc, of undoped films was found to drop from 6.5 to 1 K with decreasing thickness. Despite this reduction, the critical volume concentration of magnetic impurities, 6.5 at. % of Gd, remains independent on thickness of superconducting films. The strength of the magnetic pair-breaker (measured as an initial linear slop of Tc vs. Gd percent dependence) monotonically decreases with decreasing film thickness and becomes zero for the superconducting films with Tc =1 K. Thus, the suppression of superconductivity by reducing film thickness and by magnetic impurities are observed to be non-additive processes in amorphous Mo-Ge alloy. The anomalous behavior is likely related to the spatially inhomogeneous distribution of the order parameter

Tuesday, September 13, 2011

4:00 pm

Room 334 JFB