Pulsed-neutron diffraction studies of multi-step metamagnetism in DyRu2Si2

By pulsed-neutron diffraction experiments on a DyRu2Si2 single crystal in an external magnetic field as well as in zero field we have confirmed peculiar one- and two-dimensional spin orderings in zero field, in which two paramagnetic (2 0 0)/(1 0 0) planes and two frustrated paramagnetic Dy ions are contained in the magnetic unit cells of 9a×a×c and 9a×9a×c, respectively, and made clear magnetic structures of the field-induced-metamagnetic phases. The zero field two-dimensional magnetic structure changes to one-dimensional without any paramagnetic Dy ion at H=0.5 T, similar to the high-temperature structure. At H=1.2 T, the spin arrangement becomes again two-dimensional without any paramagnetic Dy ion, then it changes at H=1.9 T to another -two-dimensional arrangement with more ferromagnetic components, and finally undergoes a fully-induced-ferromagnetic structure. [Copyright &y& Elsevier]