Electrical Properties and AC Susceptibility of CdTe Added Tl2Ba2CaCu2O8-δ Superconductor

Abstract

Information on semiconductor/superconductor interface is important in fabricating devices of such hybrid systems. In this paper the electrical properties and AC susceptibility of Tl 2 Ba 2 CaCu 2 O 8 (Tl-2212) superconductor added with CdTe semiconductor are reported. Samples with nominal starting composition Tl 2 Ba 2 CaCu 2 O 8 (CdTe) x with x = 0 to 0.20 weight percent (wt. %) have been prepared by the solid-state reaction method. X-ray diffraction patterns showed essentially the Tl-2212 phase with presence of impurities (CuO and Tl 2 Ba 2 CuO 6 ) for x 0.05 wt. % but did not change the Tl-2212 structure which is tetragonal with lattice parameter a = b c. The critical onset temperature, T c-onset for all samples was between 104 and 108 K while the critical zero resistance temperature, T c-zero was from 93 to 95 K. The superconducting transition determined by AC susceptibility measurement showed T c' between 101 and 103 K. The peak temperature, T p of the imaginary part of the susceptibility " decreased for x = 0.05 and then increased for x > 0.05. This indicated that the superconducting grains were strongly coupled for x > 0.05 as a result of CdTe addition. The intergrain critical current density, J c at T p for the x = 0.2 sample J c (T p = 95 K) = 23 A cm -2 was the highest among all samples. This sample also showed the highest T p indicating CdTe improved the flux pinning of the Tl-2212 phase. This result can be useful in the fabrication of semiconductor/superconductor (Tl-2212) hybrid devices.