The new hydrides CeNiGeH1.6 and CeCuGeH1.0 crystallizing in the derivative hexagonal ZrBeSi-type structure

摘要

The ternary germanides CeNiGe and CeCuGe absorb hydrogen in the temperature range 393-473 K. X-ray powder diffraction and transmission electron microscopy show that the hydride CeNiGeH1.6(1) adopts the hexagonal ZrBeSi-type whereas CeCuGeH1.0(1) crystallizes in a superstructure of this type. Magnetization, electrical resistivity and thermopower measurements reveal that CeNiGeH1.6(1) is an intermediate valence compound having a Kondo temperature congruent to220(10)K smaller than that observed congruent to600(20)K for CeNiGe. On the contrary. a transition from ferromagnetism to non-magnetic ordering above 1.8 K is evidenced during the hydrogenation of CeCuGe. (C) 2003 Elsevier Inc. All rights reserved. [References: 28]