Electron beam induced structural changes in Bi2Sr2CaCu2O8+x studied by cathodoluminescence microscopy and secondary electron emission

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Sr₂CaCu₂O_8+x superconducting ceramics have been irradiated in the scanning electron microscope (SEM), and the irradiation-induced effects investigated by cathodoluminescence (CL), secondary electron emission (SEE) and X-ray microanalysis. Electron beam irradiation causes a slight Bi depletion and an inhomogeneous Ca distribution. A higher CL intensity emission is found in the irradiated areas, where besides an enhancement of the oxygen content related 2. 4 eV band, another CL bands probably related to new non-superconducting phases induced by irradiation can be observed. SEE yield measurements allow to detect an oxygen depleted region surrounding the irradiated areas. X-ray microanalysis shows that this intermediate region retains the cationic composition of the unaffected material. CL spectra from bright zones inside the same area also show a dominant 2. 4 eV emission band, which supports its relation with oxygen deficiency or rearrangement in high- superconductors.