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Titolo:
Nd substitution effects in YBa2Cu4O8 prepared using a conversion reaction from Y1-xNdxBa2Cu3O7-delta and CuO
Autore:
Valo, J; Leskela, M; Hauback, BC; Fjellvag, H; Koo, SM; Rao, KV;
Indirizzi:
Univ Helsinki, Dept Chem, FIN-00014 Helsinki, Finland Univ Helsinki Helsinki Finland FIN-00014 em, FIN-00014 Helsinki, Finland Inst Energy Technol, Dept Phys, N-2007 Kjeller, Norway Inst Energy Technol Kjeller Norway N-2007 t Phys, N-2007 Kjeller, Norway Univ Oslo, Dept Chem, N-0315 Oslo, Norway Univ Oslo Oslo Norway N-0315Univ Oslo, Dept Chem, N-0315 Oslo, Norway Royal Inst Technol, Dept Condensed Matter Phys, S-10044 Stockholm, Sweden Royal Inst Technol Stockholm Sweden S-10044 s, S-10044 Stockholm, Sweden
Titolo Testata:
INTERNATIONAL JOURNAL OF INORGANIC MATERIALS
fascicolo: 2-3, volume: 2, anno: 2000,
pagine: 269 - 276
SICI:
1466-6049(200006/07)2:2-3<269:NSEIYP>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
POWDER NEUTRON-DIFFRACTION; OXYGEN-PRESSURE; CRYSTAL-STRUCTURE; SUPERCONDUCTOR YBA2CU4O8; T-C; PHASE; GD; HO; DY; TEMPERATURE;
Keywords:
superconductors; neutron diffraction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Valo, J Univ Helsinki, Dept Chem, POB 55, FIN-00014 Helsinki, Finland UnivHelsinki POB 55 Helsinki Finland FIN-00014 Helsinki, Finland
Citazione:
J. Valo et al., "Nd substitution effects in YBa2Cu4O8 prepared using a conversion reaction from Y1-xNdxBa2Cu3O7-delta and CuO", INT J INORG, 2(2-3), 2000, pp. 269-276

Abstract

Synthesis, crystal structure and magnetic properties of samples with partial substitution of Nd for Y in YBa2Cu4O8 are considered. The samples with nominal composition Y1-xNdxBa2Cu4O8 (x=0.0-0.75) were prepared using a solidstate conversion reaction from Y1-xNdxBa2Cu3O7-8 and CuO using LiF as a flux. The annealing was performed at 790 degrees C in a flowing oxygen atmosphere. The products with x=0.0-0.5 showed thermal stability up to 660 degrees C in N-2(g) atmosphere revealing a single phase composition. The success of the synthesis is considered in relation to the effective ionic size of the Nd3+ ion. The crystal structures of the compounds are described on the basis of powder neutron diffraction measurements. The T-c values of the Nd substituted samples were noticeably lower than for the pristine YBa2Cu4Odelta. Possible reasons for the decrease in T-c are discussed on the basis of calculated values for hole concentrations in the Cu-O-2 planes obtained via the BVS (bond valence sum) method, and on the basis of some Nd3+ ions beingintroduced at Ba2+ ion sites in the lattice. (C) 2000 Elsevier Science Ltd. All rights reserved.

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Documento generato il 20/09/20 alle ore 00:33:17