Electron spin resonance investigation of the Heavy-Fermion compound CeCu2(Si1−x Ge x )2

Abstract

The Kondo-lattice system CeCu2(Si 1 xGex)2 exhibits an alloying induced transition from a coherent Fermi-liquid (x = 0) with strongly enhanced effective masses to an antiferromagnetically ordered heavy-fermion system (x = 1). This transition is studied by Gd 3+ ESR in oriented powder samples. The temperature dependence of the ESR line width follows a characteristic pattern which allows one to distinguish between the different ground states. The results obtained in polycrystalline CeCu2Si 2 are in good agreement with the measurements performed in single crystals. Finally we compare our results with 63Cu-NMR data obtained from CeCu2Si 2 and CeCu2Ge 2.