Ogawa Soichi

Thickness Dependence of Superconducting NbTi Film on T c and J c

Thickness dependencies of the superconducting properties of NbTi films with 170 to 9700A have been studied by critical temperature Tc and critical current Jc measurements at 4.2 K. The films are obtained by rf magnetron sputtering method. It is observed that Tc is almost independent of film thickness above 1000A. From 1000 to 340A, Tc slowly decreases with decreasing thickness, and such depression is remarkably quickend below 340A, e.g. 2.7K for 230A. The results were compared with those of other researchers and the extended BCS theory qualitatively. Critical current rapidly increases from the order of 104 to 106 (Acm−2) with decreasing thickness from 8000 to 230A at zero field. Also, field dependencies of Jc were measured for more thinner films than those of Stejic et al. [1].