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Local structure around cations in the T'-type Nd(Ce) based superconducting system: an EXAFS study

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Title Local structure around cations in the T'-type Nd(Ce) based superconducting system: an EXAFS study
 
Creator PADALIA, BD
OKRAM, GS
PRAKASH, O
GURMAN, SJ
AMISS, JC
 
Subject x-ray-absorption
oxygen stoichiometry
neutron-diffraction
crystal-structure
single-crystal
electron
nd2-xcexcuo4
nd1.85ce0.15cuo4-delta
defects
co
 
Description EXAFS measurements on all the cations in Nd2CuO4, Nd2-xCexCuOy (NCCO) and Nd(1.82-z)A(z)Ce(0.18)CuO(y) (NACCO), A=Sr, Ca or Ba, x = 0.06 or 0.18, have been made using synchrotron radiation. Bond lengths (R), coordination numbers (N) and Debye-Waller factors (sigma(2)) have been obtained from the EXAFS analysis. The curved wave theory in the single-scattering approximation and the small-atom multiple-scattering theory have been applied to experimental EXAFS data and it is found that the latter gives a better fit. The CuO2 plane contains a strong multiple-scattering contribution. Further, all the dopants (Ce, Sr, Ca and Ba) occupy the Nd site without affecting the basic T' structure. Doping affects the local structure around the substituents as reflected by the changes in R and sigma(2) values. The observed CuO2 layer distortion (or large Cu-O-Cu angle deviation from linearity, 180 degrees) is found to have an adverse effect an T-c as observed in Ca or Ba doped NACCO samples. Further, it is realized that critical levels of charge carriers, oxygen vacancies and CuO2 planar effects have a strong influence on the SC behaviour of the T'-type electron doped cuprates.
 
Publisher IOP PUBLISHING LTD
 
Date 2011-08-03T19:48:13Z
2011-12-26T12:54:22Z
2011-12-27T05:42:14Z
2011-08-03T19:48:13Z
2011-12-26T12:54:22Z
2011-12-27T05:42:14Z
1997
 
Type Article
 
Identifier JOURNAL OF PHYSICS-CONDENSED MATTER, 9(44), 9695-9714
0953-8984
http://dx.doi.org/10.1088/0953-8984/9/44/023
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9134
http://hdl.handle.net/10054/9134
 
Language en