Valence studies on various superconducting bismuth and lead cuprates and related materials
✍ Scribed by M. Karppinen; A. Fukuoka; J. Wang; S. Takano; M. Wakata; T. Ikemachi; H. Yamauchi
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 541 KB
- Volume
- 208
- Category
- Article
- ISSN
- 0921-4534
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✦ Synopsis
The oxygen contents and metal valences~have been determined in various (Bi, Pb)2Sr2( Ca, Y)Cu20:, Bi2Sr2Ca2Cu3Oz and Pbz(Ba, Y, Ca)3Cu3Oz samples by a two-step coulometrie titration method. The first titration experiment, which consists of the reactions of Cu(III), Bi(V) and Pb(IV) with CuCI followed by an anodic oxidation of the excess Cu(I), reveals the oxygen content of the sample. In the second experiment the valences of bismuth and lead are distinguished from the Cu-valence by taking advantage of the reaction with Fe(II). By performing the first experiment without adding CuC1 it was even possible to evaluate the distinct valence values for erystallographically different copper atoms when the sample contained both Cu (Ill) and Cu (I) in separate Myers. The applicability of the employed analysis procedures as well as the results obtained for the studied materials are discussed.