Study of grain boundary properties in Ag-clad Bi₂Sr ₂Ca₂Cu₃O_x tapes by multi-phase electron backscatter diffraction analysis

The properties of grain boundaries within Ag-clad (Pb,Bi) ₂Sr₂Ca₂Cu₃O_x (Bi-2223) tapes are studied by means of electron backscatter diffraction (EBSD). The achieved high image quality of the Kikuchi patterns enables multi-phase EBSD scans including Bi-2223, Bi₂Sr₂CaCu₂O _x (Bi-2212), Bi₂Sr₂CuO_x (Bi-2201), (Sr,Ca)₁₄Cu₂₄O₄₁ and Ag to be performed. For the EBSD scans a maximum spatial resolution of 30 nm was reached enabling a detailed orientation analysis. The nature of the grain boundaries is discussed on the base of the EBSD data. While the main orientation of the tape is in [0 0 1] direction, a large number of misorientations is detected. These misorientations are visualized using crystal direction (CD) maps. Furthermore, EBSD enables the spatially resolved mapping of the misorientation angles within each phase separately. The influence of these grain boundaries on the current transport properties is discussed.