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Effects of Ce substitution and and reduction on the electronic states of Nd sub 2 minus x Ce sub x CuO sub 4 minus y studied by x-ray photoelectron

Journal Article · · Physical Review, B: Condensed Matter; (USA)
;  [1];  [2]; ; ;  [3]
  1. Steel Research Center, NKK Corporation, Kawasaki 210 (Japan)
  2. Research Institute of Electronics, Shizuoka University, Hamamatsu 432 (Japan)
  3. Institute for Materials Research, Tohoku University, Sendai 980 (Japan)

The effects of Ce substitution and reduction on the core levels and valence electronic states of Nd{sub 2{minus}{ital x}}Ce{sub {ital x}}CuO{sub 4{minus}{ital y}} have been investigated using x-ray photoelectron spectroscopy (XPS). It is found that the surfaces could be tremendously degraded by scraping, leading to changes in the electronic structures of Cu, O, and the Fermi edge. The changes in the Cu 2{ital p} spectra imply that the Ce substitution and the reduction donate electrons to Cu sites to show the appearance of monovalent Cu. The fraction of monovalent Cu derived from the Cu 2{ital p} spectra is less than the amount of Ce, which suggests that Ce is in the mixed-valence state. The XPS valence spectra show the Fermi edge formed by the electrons injected into the electronic state with the Cu 3{ital d}{sup 10} configuration. The nature of the Fermi edge is discussed in terms of photoionization cross section.

OSTI ID:
6339010
Journal Information:
Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Journal Issue: 7 Vol. 42:7; ISSN PRBMD; ISSN 0163-1829
Country of Publication:
United States
Language:
English