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Polycrystalline (Pr1−xBax)Ba2Cu3O7−δ samples (0.0 ≤ x ≤ 0.6) is prepared by the standard solid state reaction technique. X-ray measurements confirm the formation of the 123 phase for x ≤ 0.3, but for 0.4 ≤ x ≤ 0.6, due to the solubility limit, the 123 phase is not a dominant phase. Resistivity measurements show the increasing of resistivity with the increase of Ba-doping up to about x = 0.08, and then decreases in the 123 phase up to x = 0.3. There is no observation of superconducting state in our samples, but we observe the sharp decrease of resistivity for x > 0.1, which is related to possible superconductivity in Pr123 system by Ba-doping. It is concluded that the Pr/Ba disorder has important effect in the transport electrical properties, specially occuring a superconducting state in Pr123. It is also suggested that extra Ba concentration in Pr123 system can create superconducting state such as in Ca-doped Pr123. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) |
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