Powder Sample Susceptibility for Single Ion Magnets with S = 1, 3=2 with Rhombic Anisotropy.

In this paper, the general analysis of powder sample magnetic susceptibility of single ion magnets displaying axial (D) and rhombic (E) local anisotropy, and characterized by the isotropic spectroscopic tensor g, is conducted. The aim is to obtain exact expressions for the temperature dependence of magnetic susceptibility to extract both anisotropy parameters D and E from the powder susceptibility data. Two cases are considered, with integer (S = 1) and half-integer (S = 3=2) spin. In the former, the procedure based on the low-temperature behavior of the susceptibility signal, which effectively reduces the number of fitting parameters, is proposed. By contrast, in the case of the SIM with S = 3=2, it is explicitly demonstrated that the powder susceptibility depends on the combined anisotropy parameter Δ = √ D² + 3E², precluding the full resolution of the axial and rhombic anisotropy constants. [ABSTRACT FROM AUTHOR]