A ATUDY ON SUPERCONDUCTING FILMS OF Nb(As) PRODUCED BY ARSENIC ION IMPLANTATION

Superconducting film is prepared by implanting high dose As ions with 150keV into Nb film on the microcrystallite glass substrates, and annealing at thetemperature of 800℃ for 30 minutes. in the vacuum of 1.3×10~(-5) Pa. Thesuperconducting transition temperature, T_C, equals 6.6K. The thickness of implan-tation layer is about 67 nm. The concentration profile of arsenic in the implanta-tion layer is measured by iterative subtracting backscattering spectrum method.The concentration ratio of Nb atom to As atom, N_(Nb)/N_(A?)=2.2, isobtained. Consequently, the sample is not an ideal Nb_3As of Ti_3P configurationbut a Nb rich superconductor film of Nb(As). However, its superconductingtransition temperature is higher than that of Nb_3As of Ti_3P type. The latter'stransition temperature is 0.3 K only.