HREM of Ceramic High T_c Superconductors

摘要

High resolution electron microscopy (HREM) is a real space technique, able to provide structural information complementary to the reciprocal space techniques such as X-ray or neutron diffraction. While the latter produce average information, HREM provides local information down to atomic scale. For ceramic high temperature superconductors not only the perfect structure is of importance, but particularly the defect structure or local structure. Physical properties such as critical current or superconducting volume fraction are strongly influenced by the deviations from perfection. We will further show that light element configurations— such as ogygen ordering or the incorporation of carbonate groups in the material—can be identified on atomic resolution images.