Control of hole distribution through isovalent R-cation substitution in Cu[sub 2]Ba[sub 2]RCu[sub 2]O[sub 8] superconductors

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Journal Title
Journal ISSN
Volume Title
School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2007
Major/Subject
Mcode
Degree programme
Language
en
Pages
032511/1-3
Series
Applied Physics Letters, Volume 90, Issue 3
Abstract
Superconductive Cu2Ba2RCu2O8 samples with R ranging from Gd to Tm have been synthesized through a sol-gel route. Both iodometric titration and CuL-edge x-rayabsorption near-edge structure (XANES)spectroscopy data indicate that the average Cu valence remains constant, whereas Tc increases with decreasing size of the R constituent. An explanation for this trend is revealed from O K-edge XANESspectra, which show that the smaller-for-larger R-cation substitution results in a shift of holes from the Cu2O2 charge reservoir to the superconductive CuO2 planes. Since Cu2Ba2RCu2O8 samples are underdoped, such a shift of holes raises the value of Tc.
Description
Keywords
superconductors, copper
Other note
Citation
Karppinen, Maarit & Abe, Y. & Grigoraviciute, I. & Chen, J. M. & Liu, R. S. & Yamauchi, H. 2007. Control of hole distribution through isovalent R-cation substitution in Cu[sub 2]Ba[sub 2]RCu[sub 2]O[sub 8] superconductors. Applied Physics Letters. Volume 90, Issue 3. 032511/1-3. ISSN 0003-6951 (printed). DOI: 10.1063/1.2431458.