Investigations of magnetic interactions and spin-Hamiltonian parameters for 4B1 (3d3) state ion in a tetragonal crystal field

The magnetic interactions as well as the microscopic origins of the spin-Hamiltonian (SH) parameters including b(2)(0), g(//), g(perpendicular to), Delta(g) for B-4(1) (3d(3)) state ion in a tetragonal crystal field have been investigated using the complete diagonalization method (CDM) It is found that the contribution to the spin-Hamiltonian parameters arising from the spin-orbit (SO) magnetic interaction is the most important for most part of the crystal field (CF) ranges. However, the contributions to the zero-field split (ZFS) parameter b(2)(0) from the other three mechanisms including the SS mechanism and SOO mechanism as well as SO-SS-SOO combined coupling mechanism exceed 20% for most part of the CF ranges, especially for some CF ranges, in which the contributions to the ZFS parameter b(2)(0) from the other three mechanisms exceed that from the SO mechanism. It is shown in present studies that the approximate expression of ZFS parameter b(2)(0) developed by Macfarlane is not convergent for most part of the CF ranges. The microscopic origins of the splitting in the lowest existing state E-2(g) are studied. Different mechanisms of the splitting E-2(g) state for C-4 nu and C-3 nu crystal fields are explained using group theory.