Application of electron backscatter diffraction to bulk high-Tc superconductors

Abstract

We have successfully obtained electron backscatter diffraction (EBSD) Kikuchi patterns on various bulk high-Tc superconductors (polycrystalline KClO3-doped and undoped YBa2Cu3O7−δ (YBCO), single crystalline YBCO and NdBa2Cu3O7−y) and on YBCO and NdBCO thin films. We have established a sample polishing procedure to obtain intense Kikuchi patterns without an additional carbon coating of the ceramic superconductors. We present Kikuchi patterns, pole figures and orientation maps of the samples. On the polycrystalline KClO3-doped YBCO samples we find two major orientations (001) and (100) normal to the sample surface, while the undoped sample does not exhibit any orientation maxima, which is ascribed to the effect of a liquid phase due to the KClO3-additive during the preparation process. Furthermore, we discuss the future possibilities for the application of the EBSD technique for growing larger, bulk melt-textured samples for applications.

Second Step in the Field-Cooled Magnetization of Bi-2212 Single Crystals

“…The secondary peak is only seen at small fields, below the second step in the transition curves the presence of a secondary phase, it might be possible to prepare pure samples by further improving the processing conditions. This also implies that conclusions concerning the vortex phase diagram [3] have to be reconsidered carefully; especially the origin of the secondary peak might not be an indication of a phase transition in the vortex lattice, but might be due to the presence of a weaker superconducting phase; hence the origin of the secondary peak effect might be of the same type as in the superconductors with the 123-structure [9]. To conclude, we have found that FCC and ZFC-W curves of Bi-based superconductors show a second step in the superconducting transition in fields above 4 T. This second step is directly linked to the secondary peak effect, and to the steep increase of j c at temperatures below 20 K, as observed in all Bi-based superconductors.…”

Crystallographic Orientation Analyses of Magnetite Thin Films Using Electron Backscatter Diffraction (EBSD)

“…Based on the analysis of the recorded CI value, a multiphase analysis is realized. A detailed description of the measurement procedure can be found in [10] and [11]. The results of the EBSD measurement are presented in form of maps, the most important thereof are the so- were performed for each sample twice; one with a step size of 1 m as overview and a detail scan with a step size of 50 nm.…”

EBSD characterisation of Y2Ba4CuUOxphase in melttextured YBCO with addition of depleted uranium oxide

“…The surfaces were subsequently dry-polished using 3M polishing papers as described in Ref. [7], using only ethanol for cleaning purposes. This procedure yields high image quality Kikuchi patterns and has been demonstrated to work well even on various polycrystalline YBCO samples [7,8].…”

“…A detailed description of the measurement procedure can be found in Refs. [7,8]. Figure 1 gives the SEM/EDX-analysis of the YBCO sample with 0.8wt.-% DU addition.…”