STRAIGHTFORWARD IDENTIFICATION OF THE A-CRYSTALLINE AND B-CRYSTALLINEAXES IN YBA2CU3O7 SINGLE-CRYSTAL BY A POLARIZING MICROSCOPE SET-UP

This work presents a simple and quick method to define unambiguously t he orientation of the a and b crystallographic axes in an untwinned do main of YBa2Cu3O7-delta (delta --> 0) single crystals. The method is b ased on the analysis of the light reflected on such a domain, for norm ally incident light selected in the red spectral range. Micro-Raman sc attering measurements, which are another way to attribute the crystall ine axes, have been investigated to confirm the orientation of the a a nd b axes by polarization microscopy.