Magnetic properties in intermetallic compounds DyMn₂(Si_1-xGe_x)₂(0 ≤x≤ 1)

Magnetic measurements have been performed in order to investigate magnetic properties of pseudo-ternary compounds DyMn₂(Si_1-xGe_x)₂(0 ≤x≤1). As _x increases, lattice parameters increase from a = 3.904 A ̊ and c = 10.41 A ̊ at x = 0 to a = 3.975 A ̊ and c = 10.79 A ̊ at x = 1, and the Néel temperature decreases from 523 to 430 K. In all the compounds, magnetic transitions are observed at low temperatures where Dy moments start to order magnetically. DyMn₂Si₂ has three magnetic phases below 38 K whose magnetic structures are long-periodic, and it is supposed that there occurs a magnetic short-range order of Dy moments between 38 and 83 K. The compounds with 0.1 ≤x≤ 0.6 have a magnetic phase below about 25 K with a canted-ferrimagnetic structure. This phase exists up to x = 0.9, although DyMn₂Ge₂ has a collinear-ferrimagnetic phase. For 0.7 ≤x≤ 1.0, there exists an intermediate-temperature phase which may have a ferrimagnetic structure with a long-periodic arrangement.