Abstract
The Ni(NCS)2 (pyzdo)2 coordination polymer is found to be an S = 1 spatially anisotropic square lattice with easy-axis single-ion anisotropy. This conclusion is based upon considering in concert the experimental probes x-ray diffraction, magnetic susceptibility, magnetic-field-dependent heat capacity, muon-spin relaxation, neutron diffraction, neutron spectroscopy, and pulsed-field magnetization. Long-range antiferromagnetic (AFM) order develops at TN = 18.5 K. Although the samples are polycrystalline, there is an observable spin-flop transition and saturation of the magnetization at ≈80 T. Linear spin-wave theory yields spatially anisotropic exchanges within an AFM square lattice, Jx=0.235 meV, Jy=2.014 meV, and an easy-axis single-ion anisotropy D=−1.622 meV (after renormalization). The anisotropy of the exchanges is supported by density functional theory.
