Magnetic Phase Diagram of DyNi₂Si₂ with Two-Dimensionally Modulated Spin Structures

抄録

The fully mapped T-H (temperature-magnetic field) phase diagram of DyNi₂Si₂ has been determined by heat capacity and magnetic susceptibility measurements. In zero magnetic fields, the heat capacity exhibits a small but distinct cusp at T₁=3.7 K corresponding to the magnetic order-order phase transition, and a clear λ-type transition at T_N=5.6 K. Except for the paramagnetic phase, three magnetic phases are found below T_N and below the critical field H_c=21.5 Oe. The results are discussed in comparison with recent experimental evidence which indicates the two-dimensionally modulated spin structures in the c-plane.