COMBINED SIMS-ISS STUDY OF THE HIGH-T-C SUPERCONDUCTING COMPOUND YBA2CU3-YALYOX

Secondary ion yields, secondary ion-energy spectra and ion-scattering spectra for high-T-c superconducting compound YBa2Cu3-yAlyOx have been studied as a function of A1 content (y = 0-0.8). In accordance with d ata known from literature, it was shown by Secondary-Ion Mass Spectrom etry (SIMS) that A1 doping of YBaCuO results in the selective substitu tion of Cu1 atoms with A1 atoms. The correlated non-monotonic variatio ns of the secondary-ion yield, the most probable secondary ion energy and the scattered ion yield for Y and Ba were observed with a growth o f A1 concentration and were explained in terms of the modification of local composition and electronic structure in the vicinity of these at oms. The kinetics of secondary-ion emission during sputtering of the o riginal surface layer degraded under air exposure has also been measur ed for the YBaCuAlO samples. It was found that the ion currents ratio Ba+/BaOH+ may characterize the level of degradation and the oxygen con centration in Cu1-O layers.