Nuclear spin lattice relaxation time T1 of Cu63 was measured for Cu/Nb multilayered sample, in each 50 layers of Cu and Nb with thicknesses of 400 Å and 245 Å. The superconducting transition was observed by magnetic induction at Tc=4.6 K. As temperature T is lowered below Tc, the relaxation rate T1-1 is once increased and then decreased exponentialy. This behavior is characterized by the existence of superconducting energy gap 2Δ=0.96 meV=2.4 kBTc in Cu. For further lowering of T below 0.8 K, the rapid decreasing in T1-1 was replaced by a gradual change almost proportional to T.
ASJC Scopus subject areas
- Physics and Astronomy(all)