Crystal structure, electrical, and magnetic properties of the Sm2Cu0.8Ge3 compound

The crystal structure, electrical, and magnetic properties of the new ternary compound Sm2Cu0.8Ge3 have been investigated using powder X-ray diffraction, electrical resistivity, and magnetic susceptibility measurements. X-ray diffraction patterns reveal that this compound crystallizes in a tetragonal α-ThSi2 structure (space group I41/amd) with lattice parameters a = 0.413(1) nm and c = 1.420(3) nm. The irreversibility of the zero field cooled and field cooled dc magnetization data reveals the occurrence of spin glass transition with the spin freezing temperature Tf ∼ 8.5 K in this compound. Ac susceptibility and isothermal remanent magnetization data also confirm the existence of the spin glass phase. In addition, a broad maximum is observed in the ρ(T) curve near Tf. The spin glass phase is ascribed to the formation of random interaction between the Sm ions due to the irregular distribution of Cu and Ge atoms as well as the deficiency of the occupancy on the 8e crystallographic sites of the sample.