Electron spectroscopic imaging of (Bi,Pb)2Sr2Can − 1CunO4 + 2n + δ high-Tc superconducting phases in the TEM

This paper deals with the imaging of the (Bi,Pb)2Sr2CaCu2O8 + δ and the (Bi,Pb)2Sr2Ca2Cu3O10 + δ high-Tc superconducting phases by electron spectroscopic imaging in the TEM. Intergrowth of (Bi,Pb)2Sr2CaCu2O8 + δ and (Bi,Pb)2Sr2Ca2Cu3O10 + δ on the nm scale occurs on (0 0 1) planes and requires imaging conditions with the electron beam being parallel to the (0 0 1) planes. Experimental settings for the acquisition of Ca-L jump ratio images are described which yield optimum contrast between the two phases and results obtained under these conditions are shown. For the acquisition of ESI images a systematic row of (0 0 1) reflections is excited and diffraction effects with varying specimen thickness are significant. A Bloch wave calculation for estimating these diffraction effects quantitatively was carried out and yielded a substantial decrease of electron intensities in the objective aperture with increasing speciment thickness.