Flux crystal growth of CeCu2Si2: Revealing the effect of composition

Abstract

The low-temperature properties of CeCu2Si2 are extremely sensitive to deviations from stoichiometry and defects, leading to a strong dependence of the observed properties on sample preparation conditions. In the past few years we have developed a flux method which allows the growth of large single crystals with controlled physical properties. Here, we demonstrate that the Ce content in the starting melt, one of the most important parameters in our growth process, mainly influences the Cu/Si ratio in the single crystals but not their Ce content. A higher Cu/Si ratio yields a smaller c/a ratio, while the unit cell volume remains roughly constant. We observe a clear correlation between the Cu/Si ratio and the physical properties, showing that electronic effects are more important than volume effects. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim