Distinguishing between YBa2Cu3O7-x and Y2BaCuO5 in melt-processed YBa2Cu3O7-x
Much of the work in high temperature superconducting ceramics in the last few years has been aimed at improving the critical current density (Jc). By melt-texturing samples it is possible to achieve a significant increase in the Jc of bulk YBa2Cu3O7-x (Y123). It has been known for some time that additions of Y2Ba2CuO5 (Y211) in the Y123 superconductor can improve the Jc. However, for the maximum improvement the Y211 particles must be very fine and well distributed throughout the sample. Thus it is clearly of considerable interest to be able to examine a bulk sample and be able to easily distinguish between the Y123 and Y211 particles. By a combination of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) it is possible to study grain size, inclusion size and dislocation structure in the same sample.