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Structural, magnetic and magneto-transport studies on the (La2/3Sm1/3)(0.67)Ba0.33-xSrxMnO3 (x=0, 0.1, 0.2 and 0.33) manganites

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Title Structural, magnetic and magneto-transport studies on the (La2/3Sm1/3)(0.67)Ba0.33-xSrxMnO3 (x=0, 0.1, 0.2 and 0.33) manganites
 
Creator ASTHANA, S
BAHADUR, D
 
Subject colossal magnetoresistance
cation disorder
transport
ca
mechanism
 
Description The effect of substituting Sr for Ba on the magneto-transport and magnetic properties of the (La2/3Sm1/3)(0.67)Ba0.33MnO3 system has been investigated. The samples of (La2/3Sm1/3)(0.67)Ba0.33-xSrxMnO3 (x = 0.0, 0.1, 0.2 and 0.33) are synthesized by the citrate gel route and crystallize in an orthorhombic structure. The unit cell volume decreases while the metal-insulator transition temperature (T-MI) increases with increasing Sr content. The atomic disorder, which is represented by the size variance, increases with Ba content. The small anomaly in rho(T) due to the atomic disorder which leads to the different magnetic ordering followed by a broad metal-insulator transition is observed in Ba-rich systems. The peak at T* (small anomaly) is presumed to be due to spin-dependent interfacial tunnelling that causes the difference in magnetic order between the surface and the core. The suppression in the resistivity values with increasing Sr content could be due to the more symmetric MnO6 octahedra network. The paramagnetic phase coexists with the magnetically ordered phase between T* (similar to T-C) and T-MI. The suppression of the metastable magnetic phase leads to the high magnetoresistance in Ba-rich samples. The transport data has been analysed using a small polaron correlated model. The magnetic behaviour may be understood by the Ising model. The overall magnetic behaviour could be accounted for by the competing antiferromagnetic and ferromagnetic interactions.
 
Publisher IOP PUBLISHING LTD
 
Date 2011-08-04T00:58:43Z
2011-12-26T12:54:28Z
2011-12-27T05:42:24Z
2011-08-04T00:58:43Z
2011-12-26T12:54:28Z
2011-12-27T05:42:24Z
2007
 
Type Article
 
Identifier JOURNAL OF PHYSICS D-APPLIED PHYSICS, 40(7), 1839-1844
0022-3727
http://dx.doi.org/10.1088/0022-3727/40/7/001
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9193
http://hdl.handle.net/10054/9193
 
Language en