Evolution of magnetic structure of Dy(Co_xNi_1−x)₂B₂C

Abstract

DyNi$_{2}$B$_{2}$C superconducts at $T_{c} \approx 6\,{\text{K}}$ and orders antiferromagnetically at $T_{N}\approx 10\,{\text{K}}.$ Its non-superconducting isomorph DyCo$_{2}$B$_{2}$C is a ferromagnet with $T_{C}\approx 6\,{\text{K}}.$ With the aim of mapping out the magnetic properties, in particular magnetic structures, of their solid solutions, we synthesized $^{11}$B-enriched Dy(Co$_{x}$Ni$_{1-x}$)$_{2}$B$_{2}$C ($x=0.2,0.4,0.6,0.8$). We investigated the evolution of their magnetic, thermal and transport properties by means of the magnetization, resistivity, specific heat and neutron diffraction techniques. Their crystal structures were confirmed to be ThCr$_{2}$-Si$_{2}$-type tetragonal (I4/mmm) phase. The magnetic structure was found to be antiferromagnetic with k_0.2 = (0, 0, 1) for x = 0.2; helicoidal with k$_{0.4}$ = (0, 0, 0.49) and k$_{0.6}$ = (0, 0, 0.46) for, respectively, x = 0.4 and 0.6 and ferromagnetic with k$_{0.8}$ = (0, 0, 0) for x = 0.8. We discuss the evolution of such magnetic modes assuming a scenario of an idealized one-dimensional chain of transverse magnetic moments.