A Comprehensive Research on New DyCo ₂Mn _x ( x = 0.0 -1.0) Laves Phases

DyCo2Mnx(x = 0.0, 0.2, 0.4, 0.6, and 1.0) compounds were successfully synthesised and characterized to be single phase, isostructural to DyCo2 with typical MgCu2 Laves phase cubic structure ( Fd-3m ) at room temperature. DyCo2 Mn exhibits a huge coercivity field HC = 21170 Oe at 5 K. The nature of the magnetic transition around TC transformed from first order for DyCo2 to second order for Mn added components. Using Kouvel-Fisher plot, critical isotherm analysis, and Arrott-Noaks plot techniques, a detailed critical exponents analysis on the nature of all the second-order transitions has been carried out: the critical exponents β ≈ 0.5, γ ≈ 1.0 and δ ≈ 3.0 were derived out indicating that all the second order transitions belong to Mean-field theory with long-range magnetic interaction during the magnetic transitions. High-resolution synchrotron x-ray measurements clarify that the crystal structure transitions synchronize with the magnetic-state transitions from paramagnetism to ferrimagnetism (PM-FM) at Curie temperature TC: the crystal structures transform from cubic (Fd-3m) to tetragonal (I41/amd) for components with x = 0.0 and 0.2, while staying with cubic (Fd-3m) structures for components with x = 0.4, 0.6 and 1.0.