Texture Investigations on High Temperature Superconductors

Abstract

The formation of a structure with strong crystallographic texture is an important requirement for high critical current densities at 77 K in high temperature superconductive materials (HTSC). In this work several methods for texture investigation in the superconductive phase of BiPbSrCaCuO/Ag-and YBaCuO/AgPd-composite conductors prepared according to the "powder in tube"-method as well as in YBaCuO-thick layers are presented. For the characterisation of the texture development in dependence on technological steps at the preparation of HTSC-composite conductors the determination of the halfwidth FWHM from the psi-scan or for one-phase specimens the determination of the Lotgering-factor is appropriate, if only a c-axis exists. The measurement of pole figures is necessary to determine, whether a rotation symmetry occurs or an orientation of the (a,b)-directions exists. The use of the omega-scan to determine the half-width is not useful, if the goniometer unit is intended and optimised for phase analysis and therefore the secondary monochromator cannot be relinquished.