Spin Hamiltonian Parameters for Co²⁺Ions in PbMoO₄Crystal - Interplay between the Fictitious Spin S'=1/2 and the Effective Spin S̃ =3/2

Abstract

2+ IonsThe interplay between the fictitious spin S = 1/2 and the effective spinS = 3/2 for Co 2+ (3d 7 ) ions is considered. The available experimental data on the Ze g i factors for the two Co 2+ complexes in PbMoO4 obtained using the fictitious "spin" S = 1/2 description serve for determination of the Zeeman gi factors corresponding to the effective spinS = 3/2. The second-rank zero-field splitting parameters D and E (S = 3/2) are also indirectly determined from the experimental EMR data by employing the formulas arising from projection of the gi(S = 3/2) factors onto the g i (S = 1/2) factors. The so-determined second-rank zero-field splitting parameters and gi(S = 3/2) factors will enable comparison with the respective quantities obtained in a subsequent paper using a combined modeling approach.

Origin of the Ground Kramers Doublets for Co2+(3d7) Ions with the Effective Spin 3/2 Versus the Fictitious ‘Spin’ ½

“…3, we note that for the effective spin Hamiltonian, the ZFS magnitude does not affect the g-tensor at all. However, for the fictitious spin S′ = 1/2 Hamiltonian, the g'-tensor is indeed related to the effective spin ZFS parameters, see, e.g., [34,35]. On the other hand, the symmetry of the g-and g'-tensors as well as the ZFS tensor is determined by symmetry of the system and their explicit forms depend on the selected axes in which these tensors are expressed.…”