Structural and magnetic properties in the polymorphs of CeRh0.5Ge1.5

• A new compound CeRh0.5Ge1.5 in two difference phases was synthesized by arc melting.
• The crystal structure of both compounds was determined from the single crystal XRD.
• Isothermal relaxation measurements suggesting spin-glass like anomalies in both phases.

We investigate the structural and magnetic properties in the polymorphs of a new compound CeRh0.5Ge1.5. Depending upon the starting materials, and the slightly different synthesis method, we find that CeRh0.5Ge1.5 compound exists in two different space groups. The first compound, α-CeRh0.5Ge1.5 crystallizes in tetragonal α-ThSi2 structure type in space group I41/amd with lattice parameters, a=4.2034(6) Å and c=14.770(3) Å. In this structure, the cerium atoms occupy the position between the Rh/Ge tetrahedral layers. On the other hand, the second compound, namely β-CeRh0.5Ge1.5 crystallizes in the AlB2 type hexagonal structure in space group P6/mmm, with lattice parameters, a=4.2615(7) Å and c=4.1813(9) Å. The crystal structure of β-CeRh0.5Ge1.5 consists of two dimensional Rh/Ge hexagonal units and the cerium atoms are sandwiched between them. Magnetization studies exhibit magnetic ordering, as evident from a sharp peak in the plot of magnetic susceptibility measured as a function of temperature in a fixed magnetic field, in α-CeRh0.5Ge1.5 and β-CeRh0.5Ge1.5 at 3.6 K and 12 K, respectively. Structural and magnetic properties of both compounds are presented and discussed here.

Two polymorphs of a new compound CeRh0.5Ge1.5 in the α-ThSi2 and AlB2 structure types were synthesized by arc melting. The magnetic measurements of both CeRh0.5Ge1.5 phases suggest spin-glass behavior.Figure optionsDownload as PowerPoint slide