Formalism of the Rhombic Spin Hamiltonian with S = 2 and Its Application to EPR Spectra of Copper Aggregates in TGFB: Cu2+

Publisher Website
Google Scholar
Abstract
The properties of the spin Hamiltonian for S = 2 in a crystal field of rhombic symmetry are analysed up to terms with a, b, c proportional to the fourth power of spin operators, and a method for the determination of constants of this Hamiltonian is proposed. By perturbation calculation, the parameters a, b, c are shown to affect very strongly the anisotropy of the EPR spectrum; in certain directions, they can lead to new extrema in the graphs of EPR spectrum anisotropy. The results are applied to the description of the EPR spectrum of copper aggregates in TGFB. The spin Hamiltonian parameters are determined, and the spin level energies are given as function of the magnetic field strength. Full agreement with the experimental data is achieved showing, in conjunction with other data in reference [8], that in Cu2+‐ion‐admixtured TGFB there are present four‐ion copper complexes with spin S = 2 coupled by exchange interaction.
Keywords