Structural phase transition of CeAuGe at high pressure

Abstract

Abstract Structural properties of the ternary intermetallic compound CeAuGe were investigated at hydrostatic pressures up to 15 GPa with high-resolution angle dispersive X-ray powder diffraction using synchrotron radiation and the diamond anvil cell technique. At 8.7(7) GPa a first order phase transition is observed from a hexagonal NdPtSb-type arrangement into an orthorhombic high-pressure modification with a TiNiSi-type crystal structure. The transformation is associated with a 3% shortening of the lattice parameter perpendicular to the puckered layers [AuGe]n and an elongation of one of the lattice parameters within the plane of the layers. The changes of interatomic distances are more pronounced than the metrical alterations and indicate that a transition from layer-type poly anions into a 3D network [AuGe]n is associated with the structural transformation.