Study of the localization and Cooper pair breaking in Tl1-xErxBa2Ca2Cu3O9-delta

A series of high-temperature superconductors of type Tl1-xErxBa2Ca2Cu3O9-de lta with x ranging from 0 to 0.3 are prepared at 860 degrees C for 3.5 h. T he x-ray diffraction, scanning electron microscopy and electrical resistivi ty measurements for the prepared samples are reported. The x-ray data indic ate that the replacement of the Tl3+ ions by the magnetic Er3+ ions does no t change the structure until x = 0.3 and the solubility limit is found to b e around x(s) = 0.2. The transition temperature T-c, determined from electr ical resistivity data, shaw a depression in its value by increasing the Er content. The depression in T-c is explained to be, according to the Abrikos ov and Gor'kov model, due to the breaking of electron pairs or to the local ization effect. The critical content of Er3+ ions, the content at which the superconductivity disappears, is estimated to be at x(c) = 0.28.