Neutron scattering from magnetic polymers

Some of the static and dynamic properties of a simple magnetic polymer are calculated. The localized magnetic moments on each monomer interact via a nearest-neighbor Heisenberg exchange. While k→-independent quantities, like the free energy and the spin-wave density of states are independent of polymer conformation, k→-dependent quantities like the wave-vector-dependent susceptibility χ(k→) and the neutron scattering law S(k→,ω) can yield useful information about the polymer conformation statistics. Explicit expressions are derived for these quantities for a freely jointed polymer chain. It is shown that the inverse correlation length in a ferromagnetic polymer, which can be determined from χ(k→), goes as T12. The neutron scattering law S(k→,ω) measures essentially the spin-wave density of states at low temperatures although there is some weak k→ dependence.