Characterization of tetragonal Tl_2Ba_2Cu_1O_(6+δ) by cathodoluminescence microscopy

Abstract

Superconducting Tl_2Ba_2Cu_1O(6+δ) ceramics shows two broad luminescence bands centered at 430 nm (2.9 eV) and 530 nm (2.3 eV) wich can not be related to impurity phases. The intensity of the bands is inhomogeneously distributed in the sample and there is a relation between regions of different intensities with the grains observed in the scanning electron microscope. Relationship of cathodoluminescence contrast with oxygen content distribution is discussed.