Magnetic ground states of staggered and chiral integer-spin chains

We plan to study two spin-1 antiferromagnets, where the Ni(II) ions are connected in (i) a staggered and (ii) chiral-chain structure. Previous studies of similar spin-1/2 Cu(II) systems revealed a host of interesting magnetic properties, such as a magnetic-field-induced energy gap and family of exotic excitations that map on to the soliton and breather modes of the sine-Gordon equation. Spin-1 chains, however, are known to differ fundamentally from their spin-1/2 counterparts, and the structure of these materials suggests the presence of an unusual, alternating single-ion anisotropy, which adds further complexity to the magnetism. Muon-spin relaxation measurements show that the materials adopt an ordered magnetic structure below T = 2.3 K and 2.2 K. We propose to use neutron diffraction to determine the ordered magnetic structures in advance of measurements of the excitation spectra.