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Resistivity and thermoelectric power of La1−xYxSr2Mn2−zCrzO7 (x or z=0, 0.01, 0.03, 0.05 and 0.1) layered manganite

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Title Resistivity and thermoelectric power of La1−xYxSr2Mn2−zCrzO7 (x or z=0, 0.01, 0.03, 0.05 and 0.1) layered manganite
 
Creator YASSIN, OA
BHATIA, SN
 
Subject electrical transport
order disorder transitions
 
Description The electrical transport properties of La1−xYxSr2Mn2O7 and LaSr2Mn2−zCrzO7 (x or z=0, 0.01, 0.03, 0.05 and 0.1) samples were studied by means of resistivity and thermoelectric power (TEP) from 10 to 600 K in zero field. The metal–insulator transition occurs at a temperature (TMI) lower than the Curie temperature (TC). The data above TMI was analysed in terms of two conduction processes, viz. the variable range hopping (VRH) and the conduction by adiabatic hopping of small polarons (AHSP). Our resistivity data agrees with the resistivity behaviour predicted by magnetic localisation model only within a small range of temperature around TC. On the other hand it was well described both below and above TC by the AHSP model. The metal–insulator transition in both Cr and Y-doped samples smears out with increasing content of both the dopants. The decrease in TMI of the Y-doped samples appears to be governed by the cation disorder in the rocksalt layer while in the Cr-doped samples it decreases as a result of a reduction in the double exchange interaction (DEX) brought on by the substitution of Mn3+ by Cr3+. TEP was well described in terms of transport by magneto-elastic polarons. Also the exchange coupling constant (J) obtained from the TEP data was seen to decrease with the content of the Cr and Y ions.
 
Publisher Elsevier
 
Date 2009-03-16T06:36:35Z
2011-11-25T19:07:14Z
2011-12-26T13:07:18Z
2011-12-27T05:55:26Z
2009-03-16T06:36:35Z
2011-11-25T19:07:14Z
2011-12-26T13:07:18Z
2011-12-27T05:55:26Z
2001
 
Type Article
 
Identifier Journal of Alloys and Compounds 326(1-2), 69-73
0925-8388
http://dx.doi.org/10.1016/S0925-8388(01)01226-9
http://hdl.handle.net/10054/937
http://dspace.library.iitb.ac.in/xmlui/handle/10054/937
 
Language en