INVESTIGADORES
SERQUIS Adriana Cristina
artículos
Título:
On the role of the reduction step in Nd1.85Ce0.15Cu1 ± δOy: A study of thermodynamic properties and electrical resistivity at high temperature
Autor/es:
F. PRADO; A. SERQUIS; A. CANEIRO
Revista:
PHYSICA C - SUPERCONDUTIVITY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 1999 vol. 313 p. 271 - 280
ISSN:
0921-4534
Resumen:
Resistivity and thermogravimetric measurements of the equilibrium oxygen partial pressure (p(O2)) at 900°C have been performed for samples of Nd1.85Ce0.15Cu1 ± δOy with nominal copper content of 0.99 and 1.01. The equilibrium p(O2) and resistivity data indicate a dependence of both properties on the nominal Cu content (1 ± δ) of the samples. The data are analyzed considering the existence of point defects in the cationic and anionic sublattices of the T′ phase. The superconducting response of samples with accurate control of copper and oxygen content is correlated with the presence of such defects. Superconductivity appears suddenly in samples with 1 + δ > 1.00 quenched at p(O2) values just below the CuO-Cu2O equilibrium. The role of the 'reduction step' in the appearance of superconductivity is discussed in terms of two possibilities: on one hand, the existence of randomly distributed interstitial oxygen atoms and on the other hand, the removal of microstrains present in the non-superconducting samples.