Copper nonstoichiometry at high temperatures in Ndl.85Ce0.15CUl+, Oy

A. SERQUIS; F. PRADO; A. CANEIRO

PHYSICA C - SUPERCONDUTIVITY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1996 vol. 273 p. 163 - 176

0921-4534

Samples of NdL85Ce0.15Cu~+80 r with precise control of Cu content were prepared by chemical methods. The superconductingresponse, microstructural features and XRD patterns of samples annealed at Ta = 1100°C in air were studied asa function of the annealing time. The improvement of the Meissner fraction as the annealing time increases is related toan increased homogenization of the Ce distribution. The decrease of the Meissner fraction for larger annealing times isattributed to the existence of a small Cu nonstoichiometry range in the T' phase. The possibility of Cu defects in the T'phase is discussed. A pseudobinary (Nd, Ce)203-CuO phase diagram including a small region of Cu solubility around the(Nd,Ce) 2CUO4 compound is proposed.