Low-dimensional quantum magnetism in Cu(NCS)2: A molecular framework material

Abstract

Low-dimensional magnetic materials with spin-12 moments can host a range of exotic magnetic phenomena due to the intrinsic importance of quantum fluctuations to their behavior. Here, we report the structure, magnetic structure, and magnetic properties of copper ii thiocyanate, Cu(NCS)2, a one-dimensional coordination polymer which displays low-dimensional quantum magnetism. Magnetic susceptibility, electron paramagnetic resonance spectroscopy, C13 magic-angle spinning nuclear magnetic resonance spectroscopy, and density functional theory investigations indicate that Cu(NCS)2 behaves as a two-dimensional array of weakly coupled antiferromagnetic spin chains [J2=133(1)K, α=J1/J2=0.08]. Powder neutron-diffraction measurements confirm that Cu(NCS)2 orders as a commensurate antiferromagnet below TN=12K, with a strongly reduced ordered moment (0.3μB) due to quantum fluctuations.