THE 001 MICROSTRUCTURE OF HIGHLY TEXTURED YBCO CERAMIC

Whatever method is used for the texturing process (MTG or magnetical t exturing), the understanding of the correlation between the microstruc ture and the electrical and magnetic properties requires a careful cha racterization of the grains and of the arrangement of these grains in the ceramic. This paper deals with a highly textured YBa2CU307-delta c eramic, prepared by the MTG method, which shows high transport critica l current density even under a substantial magnetic field (as high as 7 tesla). The microstructure has been studied using optical microscopy , electron microscopy, theta-2theta X-ray diffraction and Laue X-ray d iffraction. These four methods can determine the orientation of the te xtured sample very well and underline the twinning phenomena of the we ll-oxygenated orthorhombic cell. The Laue X-ray diffraction results, w hich involve a 200 mum diameter area, prove that the same orientation is observed for different adjacent grains, and in this way thin grain boundaries could be favoured, leading to high electrical performance.