A macroscopic theory of the response functions for a semi-infinite Heisenberg ferromagnet, and the application to light scattering

Linear response theory and the semiclassical torque equation for magnetisation are used to calculate the response functions (or Green functions) of a semi-infinite Heisenberg ferromagnet. These response functions provide a description of the bulk spin waves and surface spin waves in the ferromagnet, together with their spectral properties. A continuous medium approach is used, so the theory is appropriate to excitations with long wavelengths. The results are used to evaluate the lineshapes and integrated intensities for light scattering from bulk and surface spin waves.