Magnetic properties and entanglement of the octanuclear nickel phosphonate-based cage

The main subject considered in this paper is the quantum magnetic properties and entanglement of an octanuclear nickel phosphonate-based cage. We measured the temperature-dependent magnetic susceptibility of this cage, which indicates the coexistence of both antiferromagnetic and ferromagnetic interactions between the magnetic centers, Ni ions with spin 1. This observation prompted us to theoretically investigate the magnetic properties of such compounds. Our theoretical calculations were compared with the experimental results for magnetic susceptibility. Additionally, we explored the magnetization plateaus and magnetic susceptibility from an external magnetic field at low temperatures. We determined the thermal entanglement (negativity) and the logarithmic negativity for the octanuclear nickel phosphonate-based cage. The observed correlation between magnetization plateau jumps and magnetic susceptibility peaks in relation to the external magnetic field suggests the need for further experimental measurements.