Structure refinements of superconducting and nonsuperconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>1.82</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>1.18</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>6</mml:mn><mml:mo>±</mml:mo><mml:mi mathvariant="normal">δ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>from neutron-diffraction data

K. Kinoshita; Fujio Izumi; Tomoaki Yamada; H. Asano

doi:10.1103/physrevb.45.5558

Structure refinements of superconducting and nonsuperconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>1.82</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>1.18</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>6</mml:mn><mml:mo>±</mml:mo><mml:mi mathvariant="normal">δ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>from neutron-diffraction data

K. Kinoshita(NTT Basic Research Laboratories), Fujio Izumi(NTT Basic Research Laboratories), Tomoaki Yamada(NTT Basic Research Laboratories), H. Asano(NTT Basic Research Laboratories)

Physical review. B, Condensed matter

March 1, 1992

10.1103/physrevb.45.5558

Cited by 49

Abstract

The crystal structures of superconducting and nonsuperconducting ${\mathrm{La}}_{1.82}$${\mathrm{Ca}}_{1.18}$${\mathrm{Cu}}_{2}$${\mathrm{O}}_{6\ifmmode\pm\else\textpm\fi{}\mathrm{\ensuremath{\delta}}}$ synthesized under ${\mathrm{O}}_{2}$ pressures of 400 and 2 atm were refined by Rietveld analysis of neutron-powder-diffraction data. These samples contained no impurities and their observed and calculated diffraction patterns were in excellent agreement. In both samples, Ca and La preferentially occupied, respectively, a 2a site in eightfold coordination and a 4e site in ninefold coordination; a slightly higher ordering was observed in the superconducting compound. An apical oxygen site was almost fully occupied. A trace of excess oxygen between two ${\mathrm{CuO}}_{2}$ planes was detected in the superconducting compound. Cu-O(1) and Cu-O(2) bond lengths differed a little between the two samples. Increases in cation ordering and in interstitial oxygen might be important factors determining superconductivity in this system.

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