TRACER DIFFUSION OF AG IN BI2SR2CAN-1CUNO2N+4

Tracer diffusion of Ag in the c direction of single crystal Bi2Sr2CaCu2Ox (2212), and in dense polycrystalline Bi2Sr2CuOx (2201) and (Bi,Pb)(2)Sr2Ca2Cu3Ox (2223) has been investigated. Concentration profiles were measured by secondary-ion mass spectrometry and by a radiotracer serial-sectioning technique for the single and polycrystals, respectively. The diffusion coefficients of Ag in the c direction of 2212 at 500 and 600 degrees C at one atmosphere of oxygen are approximately four orders of magnitude smaller than those previously measured in 2212 polycrystals by [Y. Fang, S. Danyluk, K. C. Goretta, N. Chen, M. Runde, S. J. Rothman, and J. L. Routbort, Appl. Phys. Lett. 60, 2291 (1992)]. The volume diffusivity of Ag-110 in 2223 is given by D=6.7 X 10(7) exp[( -334 +/- 12 kJ/mol/RT] cm(2)/s at temperatures from 600 to 817 degrees C, and is not very sensitive to oxygen partial pressure between 10(3) and 10(5) Pa at 760 degrees C. The diffusion coefficient of Ag-110 in 2201 is described by D=155 exp[(-196+/-6 kJ/mol)/RT].