Naslov
Phase Transformation in the System Sr_2Ln_(1-x)Ce_xMCu_2O_(8+delta) (Ln = Rare-Earth, M = Nb, Ta) and Superconductivity

Autori
Brničević, Nevenka ; Bašic, Ivan ; Planinić, Pavica ; Gržeta, Biserka ; Tonković, Maja ; Forsthuber, M. ; Hilscher, G. ; Holubar, T. ; Michor, H. ; Kirchmayr, H. ; Schaudy, G.

Izvornik
Applied Superconductivity (0964-1807) 1 (1993), 3-6; 519-526

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
superconductivity; phase transformation; substitution; rare-earth elements; niobium; tantalum; magnetic properties; structural properties

Sažetak
Structural and magnetic investigations of the series Sr_2Ln_(1-x)Ce_xMCu_20_(8+delta), Ln = Pr, Nd, Sm, Eu, Gd ; M = Nb, Ta, which can be derived from YBa_2Cu_3O_(7-delta) by replacement of the CuO4 chains with MO6 octahedra, have been performed. Substitution of the rare earth metal atoms by cerium atoms in this series causes the appearance of a second tetragonal phase. For x = 0.5 only this second tetragonal phase exists. It has a structure as that found for the superconducting compound Sr_2Nd_(1.5)Ce_(0.5)NbCu_2O_(10-delta). Between the semiconducting Sr_2Ln_(0.5)Ce_(0.5)MCu_2O_(8+delta) and superconducting Sr_2Ln_(1.5)Ce_(0.5)MCu_2O_(10-delta) compounds, keeping the Ce content constant (Ce = 0.5), the rare earth stoichiometry can be varied without changing the type of the crystal structure, with superconductivity occurring for Ln>0.9, except for Ln = Pr.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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