Magnetic Properties and Entanglement of Nickel Containing Polymer

We establish an exactly solvable Heisenberg-Ising modification of spin-1 Ni-containing polymer chain model, for [Ni(NN’-dmen)(μ-N3)2], with NN’-dmen being NN’-dimethlethyledediamine. The material has been partly studied in experiment but not for its behavior of magnetization plateaus and magnetic susceptibility at low temperatures. By exact solution, we show that the magnetization exhibits three plateaus at zero, mid, and 3/4 of the saturation value at low temperatures, when interaction parameters lie in the vicinity of the values recovered by fitting through fully Heisenberg model. The corresponding featuring peaks of magnetic susceptibility are clearly shown. We have also calculated the susceptibility in zero magnetic field versus the temperature which shows a peak around T = 12.6 K, which is compatible with the experimental results. The model also displays plateaus in thermal entanglement that capture the one-to-one correspondence between thermal entanglement and magnetization.