Localization of charge carriers by Pr in the Tl2Ba2Ca1-xPrxCu2Oy system
DSpace at IIT Bombay
View Archive InfoField | Value | |
Title |
Localization of charge carriers by Pr in the Tl2Ba2Ca1-xPrxCu2Oy system
|
|
Creator |
BHATIA, SN
CHOWDHURY, P GUPTA, S PADALIA, BD |
|
Subject |
thermoelectric-power
transport-properties single-crystals pair-breaking normal-state tc superconductivity oxides conductivity temperature |
|
Description |
We have measured the resistivity and thermoelectric power of Tl2Ba2Ca1-xPrxCu2Oy samples with xless than or equal to0.6 in the temperature range 10-300 K. T-c decreases with an increase in the Pr concentration and a crossover from a metallic to insulator state is observed in samples with xsimilar or equal to0.4. In the highly resistive samples (x>0.4) conduction is governed by the in-plane variable range hopping of the carriers while in others, localization of bosons appears to be dominating. A "spin gap" is observed in the resistivity of these samples. The resistivity and thermoelectric power show the localization of the carriers to increase with an increase in Pr concentration. These data, examined in the light of existing models of conduction by localized carriers, show a preference for the model proposed by Nagaosa and Lee wherein the fermion contribution decreases and that of the bosons increases with the increase in the Pr concentration. The Pr L-3-edge absorption data show Pr to be present in the mixed (3(+) and 4(+)) valent state. Correlating the hole density "p" determined from T-c and thermoelectric power with the valence of Pr estimated from x-ray-absorption edge measurements, we find hole filling along with hybridization to be the dominant mechanism for destablization and eventual suppression of superconductivity in these materials.
|
|
Publisher |
AMERICAN PHYSICAL SOC
|
|
Date |
2011-07-17T15:56:19Z
2011-12-26T12:50:23Z 2011-12-27T05:51:50Z 2011-07-17T15:56:19Z 2011-12-26T12:50:23Z 2011-12-27T05:51:50Z 2002 |
|
Type |
Article
|
|
Identifier |
PHYSICAL REVIEW B, 66(21), -
1098-0121 http://dx.doi.org/10.1103/PhysRevB.66.214523 http://dspace.library.iitb.ac.in/xmlui/handle/10054/4775 http://hdl.handle.net/10054/4775 |
|
Language |
en
|
|