A Model for the Transfer of Magnetic Excitons between Antiparallel Spin Sites

Abstract

A model is proposed for the transfer of magnetic excitations between antiparallel spin sites. Formulation is made for the ⁴A_2g→²E_g transition of Cr³⁺(dε³) ions in antiferromagnetic crystals. Since the spin component is not conserved in the transfer, the mechanism is attributed to the second order effect of the spin-orbit interaction similar to the anisotropic super-exchange interaction derived by Moriya. It is shown that the model gives the correct order of magnitude for the transfer matrix elements. Unfortunately, angular dependence of the transfer matrix elements characteristic to the present model does not agree with the experimental results obtained so far.