The linear and non-linear magnetic response of a tri-uranium single molecule magnet

We report here low temperature magnetization isotherms for the single molecule magnet, (UO2-L)(3). By analyzing the low temperature magnetization in terms of M = B-chi 1 +B-chi 3(3) we extract the linear susceptibility (chi 1) and the leading order nonlinear susceptibility (chi 3). We find that (chi 1) exhibits a peak at a temperature of T-1 = 10.4 K with (chi 3) also exhibiting a peak but at a reduced temperature T-3 = 5K. At the lowest temperatures the isotherms exhibit a critical field B-c = 11.5 T marked by a clear point of inflection. A minimal Hamiltonian employing S = 1 (pseudo) spins with only a single energy scale (successfully used to model the behavior of bulk f-electron metamagnets) is shown to provide a good description of the observed linear scaling between T-1, T-3 and B-c. We further show that a Heisenberg Hamiltonian previously employed by Carretta et al (2013 J. Phys.: Condens. Matter 25 486001) to model this single molecule magnet gives formulas for the angle averaged susceptibilities (in the Ising limit) very similar to those of the minimal model.