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.

Graphical abstractTwo 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 full-size imageDownload as PowerPoint slide