Nuclear spinlattice relaxation time T1 of 63Cu was measured by the field cycling method in a Cu/Nb multilayer sample, which was prepared by rf-sputtering alternately deposited in each 50 layers of Cu and Nb with thicknesses of 400 Å and 245 Å. As the temperature T is lowerd below the superconducting transition temperature Tc=4.6 K, the spin relaxation rate T-11 initially increases and then rapidly decreases. This behavior indicates the existence of superconducting energy gap 2Δ(0) = 0.96 meV = 2.4kB7″c in Cu. Below 0.8 K, the rapid exponential decrease in T-11 is followed by a gradual change almost proportional to T.
ASJC Scopus subject areas
- Physics and Astronomy(all)