THE EFFECT OF AG ELECTROMIGRATION ON THE PROPERTIES OF BIPBSRCACUO SUPERCONDUCTORS

The effect of an electric field on the diffusion of silver and compoun ds (Cu and Sr) of BiPbSrCaCuO ceramic superconductors was investigated by energy-dispersive X-ray spectroscopy (EDX), it was established tha t Ag migrates in the electric field in the form of positively charged ions with effective charge q = +0.9 +/- 0.2., The electric field also stimulates redistribution of the matrix ions Cu and Sr in the cathode direction. Effects of Ag, Cu and Sr electromigration on crystal struct ure, composition, surface morphology and superconducting properties of the near-anode and the near-cathode region of BiPbSrCaCuO samples hav e been studied by X-ray diffraction (XRD), scanning electron microscop y (SEM) and resistivity measurements. It is found that electromigratio n of Ag and components of BiPbSrCaCuO is accompanied by the formation of predominantly the Bi-2223 phase and by an increase of the critical temperature on the cathode side in comparison with that on the anode s ide of the sample. (C) 1997 Elsevier Science B.V.