Surface exchange reactions and fast grain boundary diffusion in polycrystalline materials: Application of a spherical grain model Original Research Article

Magnetic behavior of a spin-1 Heisenberg dimer is analysed in dependence on the both uniaxial single-ion anisotropy and XXZ exchange anisotropy in a zero- as well as non-zero longitudinal magnetic field. A complete set of eigenfunctions and eigenvalues of the total Hamiltonian is presented together with an exact analytical expression for the Gibbs free energy, longitudinal magnetization, longitudinal and transverse susceptibility. The obtained theoretical results are compared with the relevant experimental data of [Ni2(Medpt)2(μ-ox)(H2O)2](ClO4)2·2H2O (Medpt=methyl-bis(3-aminopropyl)amine).