Gap solitons and resonant kinks in Heisenberg ferromagnetic chains with bond alternation

Abstract

A ferromagnetic Heisenberg spin chain Hamiltonian with bond alternation is used to investigate localized excitations in magnetic systems genuine of the discreteness and nonlinearity. Gap solitons (with the vibrating frequency lying in the gap of magnon frequency bands) and resonant kinks (with the vibrating frequency lying in the frequency bands) are found. It is also shown that an optical upper cutoff soliton (with the vibrating frequency being above the magnon frequency bands) is impossible in such a system.