Measuring magnetic anisotropy and magnetic excitations in staggered and chiral spin-1 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 exotic excitations that map on the soliton and breather modes of the sine-Gordon model of quantum-field-theory. Spin-1 chains, however, are known to differ fundamentally from their spin-1/2 counterparts, and the structure of these materials suggest the presence of an unusual, alternating single-ion anisotropy. We expect that the competition between the alternating anisotropy and antiferromagnetic could give rise to a unique excitation spectrum and promote spin canting, which is conventionally solely driven by the Dzyalonshinskii-Moriya. We propose to use zero-field inelastic neutron scattering, below magnetic ordering temperatures Tc = 2.3 K and Tc = 2.2 K, at LET to quantify the energy scales governing the magnetic properties and map the excitation spectra. The data collected at LET will supplement the magnetic neutron diffraction data collected at WISH and a suite of thermodynamic measurements.