The crystal structure of CeCu 2Ge 2 under pressure

Abstract

We have investigated the effect of hydrostatic pressure p on the crystal structure of CeCu 2Ge 2 up to p = 15 GPa. The lattice parameters and the unit cell volume decrease continuously, whereas the c/a- ratio increases. A bulk module of B 0 = 98 GPa was fittet on the V( p) data. At p = 6.5 GPa, roughly the pressure where the AF-state is replaced by the SC-state, the volume of CeCu 2Ge 2 is equal to that of CeCu 2Si 2. A comparison of the structural parameters of CeCu 2Ge 2 under pressure with those of CeCu 2Si 2 at p = 0 indicates, that the 4f-hybridisation strength is determined by the CeCu hybridisation. Further, non-hydrostatic pressure has a strong influence on the behaviour of the structural parameters.