Luminescence Study of New High Tc Oxide Superconductors
We have succeeded in the observation of a characteristic x-ray excited thermally stimulated luminescence (TSL) from new high Tc superconducting systems including no rare-earth elements, e.g. Tl-Ba-Ca-Cu-0 and Bi-Sr-Ca-Cu-0. It has been found that the TSL glow curve of the Tl system significantly differs from that of the Bi system, though they share crystallographic properties in common. In TIBaCaCuO with the nominal composition of Tl:Ba:Ca:Cu = 2:2:2:3, exhibiting superconducting transition at 97 K, distinct four glow peaks have been observed, which suggests that some traps exist in this system. Their peak wavelength ranges from ultraviolet to visible region. The thermal activation energies of traps related to the glow peaks are from 0.1 eV and 0.3 eV. The cumulative x-ray irradiation time dependence of their glow peaks has been systematically investigated together with the nominal composition dependence. On the other hand, in BiSrCaCu2O, which consists of high and low Tc phases, one broad and fragile TSL glow peak has been observed around 115 K.
KeywordsGlow Curve Thermally Stimulate Luminescence Glow Peak Thermal Activation Energy Crystallographic Property
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