TRACER DIFFUSION OF AG IN BI2SR2CAN-1CUNO2N+4

Tracer diffusion of Ag in the c direction of single crystal Bi2Sr2CaCu 2Ox (2212), and in dense polycrystalline Bi2Sr2CuOx (2201) and (Bi,Pb) (2)Sr2Ca2Cu3Ox (2223) has been investigated. Concentration profiles we re measured by secondary-ion mass spectrometry and by a radiotracer se rial-sectioning technique for the single and polycrystals, respectivel y. 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 o rders of magnitude smaller than those previously measured in 2212 poly crystals 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)]. T he 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 degre es 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].