Quantitative electron probe microanalysis of high-Tc superconducting materials

Since the discovery of ceramics with superconducting properties at rather high temperatures by Bednorz and Müller great effort has been made to find new super conducting materials and to optimize them. To achieve good superconducting properties single-phase compounds with well defined stoichiometry especially with regard to the oxygen content are needed. For the determination of these material properties several macroscopical or microscopical techniques are applied; one of these is the electron probe microanalysis (EPMA). However, most of the work by EPMA reported so far is restricted to the determination of the metal elements in the compound. Thus such analyses are somewhat incomplete and inadequate since the major information about the oxygen is lacking. On the other hand the microprobe is so far the only microanalytical technique to quantify oxide compositions with adequate accuracy as could be demonstrated recently by several authors. It is the intention of this presentation to assess the capability as well as the the limits of this technique in fully analysing the composition and the compositional microstructure of cuprate superconductors.