Synthesis, structures and magnetic properties of the Eu-based quaternary tellurides EuGdCuTe3 and EuLuCuTe3

Ruseikina, A.V., Grigoriev, M.V., Garmonov, A.A., (...), Schleid, T., Safin, D.A.// CrystEngComm//

Novel heterometallic quaternary tellurides EuGdCuTe3 and EuLuCuTe3 are reported for the first time. Both compounds were obtained from the elements as single crystals using the flux-assisted synthetic approach. The crystal structure of EuGdCuTe3 was solved in orthorhombic space group Pnma with the structural type Eu2CuS3, while the crystal structure of EuLuCuTe3 belongs to orthorhombic space group Cmcm with the structural type KZrCuS3. The 3D crystal structure of EuGdCuTe3 is constructed from EuTe7 capped trigonal prisms, GdTe6 distorted octahedra as well as CuTe4 tetrahedra. The octahedra form 2D layers, further strengthened by 1D polymeric chains (CuTe4)n. These layers are separated by 1D dimeric ribbons, formed by EuTe7 capped trigonal prisms and 1D free channels. The 3D crystal structure of EuLuCuTe3 is constructed from EuTe6 trigonal prisms, LuTe6 distorted octahedra and CuTe4 tetrahedra. The latter two polyhedra also form 2D layers, which are separated by alternating 1D polymeric chains (EuTe6)n and 1D free channels. Both tellurides were found to be paramagnetic with the transition to a ferrimagnetic state at about 8 K for EuGdCuTe3 and to a ferromagnetic state at about 3 K for EuLuCuTe3.