摘要
YBa_(2)Cu_(3)O_(y)(YBCO)foam samples show an open,porous foam structure,which may have benefits for many applications of high-Tc superconductors.As the basic material of these foams is a pseudo-single crystalline material with the directional growth initiated by a seed crystal similar to standard melt-textured samples,the texture of YBCO is a very important parameter.Therefore,we analysed the local texture and grain orientation of the individual struts forming the foam by means of atomic force microscopy(AFM)and electron backscatter diffraction(EBSD).Due to the processing route starting with Y_(2)BaCuO_(5)(211),a two-phase analysis must be performed,so a high surface quality is necessary to enable an automated EBSD scan.Good quality Kikuchi patterns were obtained from both the YBCO and 211 phases.We found an inhomogeneous distribution of the residual 211 particles,which are mainly randomly oriented and have sizes ranging between 200 nm and 15μm.In contrast to this,the YBCO matrix shows a dominating orientation with cracks with a typical distance of 1-10μm.Furthermore,the analysis of strut cross-sections reveals that the entire strut is converted to the YBCO phase.
基金
We acknowledge collaborations within the European Forum for Processors of Bulk Superconductors(EFFORT),which is funded by the Engineering and Physical Sciences Research Council(EPSRC)of the UK government.
