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The normal state transport properties of NdBa2−xLaxCu3O7−δ: Evidence of localization hole by La

✍ Scribed by S.R. Ghorbani; E. Rostamabadi


Publisher
Elsevier Science
Year
2008
Tongue
English
Weight
197 KB
Volume
468
Category
Article
ISSN
0921-4534

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✦ Synopsis


The transport properties of sintered samples NdBa 2Àx La x Cu 3 O 7Àd with 0 6 x 6 0.30 have been studied in the normal state by X-ray diffraction, the resistivity, and the thermoelectric power measurements. La doping results in a larger normal state resistivity, the thermoelectric power, a lower critical temperature T c , a larger pseoudogap temperature T g , and a change from a metal-like to a semiconductorlike behavior at low temperature and high doping concentration. The strong increase in the room temperature resistivity for x P 0.05 suggested that hole filling picture is not only mechanism to decrease hole concentration but there is also another mechanism such as mobile hole localization. The results of the resistivity as a function of temperature and doping concentration was analyzed within bipolaron model while the thermoelectric power was analyzed within a phenomenological narrow band model. A good agreement between models and data were obtained. An increased tendency for localization is found within both models. Therefore, the results of both models suggested that both hole localization and hole filling mechanisms decrease the hole concentration.


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